Method and apparatus for inter-user equipment coordination signaling

ABSTRACT

Methods and apparatuses for inter user equipment (UE) coordination signaling. A method of operating a UE includes determining a first set of first sidelink (SL) resources based on SL sensing and resource exclusion; selecting a first one or more SL resources within the first determined set for reservation, transmitting information about the first one or more SL resources, and receiving inter UE co-ordination information indicating whether a SL resource in the first one or more SL resources has a conflict. The method further includes transmitting on one of the first one or more SL resources, when the one SL resource does not have a conflict; and determining a second set of SL resources based on SL sensing and resource exclusion, and selecting a second one or more SL resources within the second set for transmission and reservation, when all of the first one or more SL resources have a conflict.

CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. § 119(e) to: U.S.Provisional Patent Application No. 63/081,023 filed on Sep. 21, 2020;U.S. Provisional Patent Application No. 63/083,541 filed on Sep. 25,2020; U.S. Provisional Patent Application No. 63/084,910 filed on Sep.29, 2020; U.S. Provisional Patent Application No. 63/148,572 filed onFeb. 11, 2021; and U.S. Provisional Patent Application No. 63/191,177filed on May 20, 2021. The above-identified provisional patentapplications are hereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to wireless communicationsystems and, more specifically, the present disclosure relates to interuser equipment (UE) coordination signaling.

BACKGROUND

5th generation (5G) or new radio (NR) mobile communications is recentlygathering increased momentum with all the worldwide technical activitieson the various candidate technologies from industry and academia. Thecandidate enablers for the 5G/NR mobile communications include massiveantenna technologies, from legacy cellular frequency bands up to highfrequencies, to provide beamforming gain and support increased capacity,new waveform (e.g., a new radio access technology (RAT)) to flexiblyaccommodate various services/applications with different requirements,new multiple access schemes to support massive connections, and so on.

SUMMARY

This disclosure relates to method and apparatus for inter-UEcoordination signaling.

In one embodiment, a UE is provided. The UE includes a processorconfigured to determine a first set of first sidelink (SL) resourcesbased on SL sensing and resource exclusion and selecting a first one ormore SL resources within the first determined set for reservation. TheUE further includes a transceiver operably connected to the processor.The transceiver is configured to transmit information about the firstone or more SL resources and receive inter UE co-ordination informationindicating whether the first one or more SL resources have a conflict.The processor is further configured to configure the transceiver totransmit on one of the first one or more SL resources, when the one SLresource does not have a conflict, and determine a second set of SLresources based on SL sensing and resource exclusion, and selecting asecond one or more SL resources within the second set for transmissionand reservation, when all of the first one or more SL resources have aconflict.

In another embodiment, another UE is provided. The UE includes atransceiver configured to receive information about one or more SLresources indicated as reserved from a second UE. The UE furtherincludes a processor operably connected to the transceiver. Theprocessor configured to determine whether there is a conflict in the oneor more SL resources indicated as reserved. The transceiver is furtherconfigured to transmit inter UE co-ordination information indicatingwhether the one or more SL resources indicated as reserved have theconflict.

In yet another embodiment, a method of operating a UE is provided. Themethod includes determining a first set of first SL resources based onSL sensing and resource exclusion; selecting a first one or more SLresources within the first determined set for reservation, transmittinginformation about the first one or more SL resources, and receivinginter UE co-ordination information indicating whether a SL resource inthe first one or more SL resources has a conflict. The method furtherincludes transmitting on one of the first one or more SL resources, whenthe one SL resource does not have a conflict; and determining a secondset of SL resources based on SL sensing and resource exclusion, andselecting a second one or more SL resources within the determined secondset for transmission and reservation, when all of the first one or moreSL resources have a conflict.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example base station (BS) according to embodimentsof the present disclosure;

FIG. 3 illustrates an example UE according to embodiments of the presentdisclosure;

FIGS. 4 and 5 illustrate example wireless transmit and receive pathsaccording to embodiments of present disclosure;

FIG. 6 illustrates an example SL network according to embodiments ofpresent disclosure;

FIG. 7 illustrates a timeline for a SL transmission on a future SLresource according to embodiments of present disclosure;

FIGS. 8 and 9 illustrate example methods for a UE according toembodiments of present disclosure;

FIG. 10 illustrates an example of separate resource pools for SL datatransmission and SL signaling according to embodiments of presentdisclosure;

FIG. 11 illustrates an example for mapping signaling resources to SLslots of a SL data resource pool according to embodiments of presentdisclosure;

FIG. 12 illustrates an example signaling using a physical sidelinkcontrol channel (PSCCH) according to embodiments of present disclosure;

FIGS. 13A-13F illustrate example physical sidelink feedback channel(PSFCH) signaling according to embodiments of present disclosure; and

FIG. 14 illustrates an example signaling using a PSCCH or physicalsidelink shared channel (PSSCH) for a resource reservation for a SLtransmission on a future SL resource according to embodiments of presentdisclosure.

DETAILED DESCRIPTION

FIGS. 1 through 14 , discussed below, and the various embodiments usedto describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably-arranged system or device.

The following documents are hereby incorporated by reference into thepresent disclosure as if fully set forth herein:

-   U.S. patent application Ser. No. 17/139,908 filed on Dec. 31, 2020;-   3GPP TS 38.211 v16.1.0, “NR; Physical channels and modulation;”-   3GPP TS 38.212 v16.1.0, “NR; Multiplexing and Channel coding;”-   3GPP TS 38.213 v16.1.0, “NR; Physical Layer Procedures for Control;”-   3GPP TS 38.214 v16.1.0, “NR; Physical Layer Procedures for Data;”-   3GPP TS 38.321 v16.0.0, “NR; Medium Access Control (MAC) protocol    specification;”-   3GPP TS 38.331 v16.0.0, “NR; Radio Resource Control (RRC) Protocol    Specification;” and-   3GPP TS 36.213 v16.1.0, “Evolved Universal Terrestrial Radio Access    (E-UTRA); Physical layer procedures.”

To meet the demand for wireless data traffic having increased sincedeployment of the fourth generation (4G) communication systems, effortshave been made to develop and deploy an improved 5th generation (5G) orpre-5G/NR communication system. Therefore, the 5G or pre-5Gcommunication system is also called a “beyond 4G network” or a “postlong term evolution (LTE) system.”

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as toaccomplish higher data rates or in lower frequency bands, such as 6 GHz,to enable robust coverage and mobility support. To decrease propagationloss of the radio waves and increase the transmission distance, thebeamforming, massive multiple-input multiple-output (MIMO), FullDimensional MIMO (FD-MIMO), array antenna, an analog beam forming, largescale antenna techniques are discussed in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud RadioAccess Networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul, moving network, cooperativecommunication, coordinated multi-points (CoMP), reception-endinterference cancellation and the like.

The discussion of 5G systems and frequency bands associated therewith isfor reference as certain embodiments of the present disclosure may beimplemented in 5G systems. However, the present disclosure is notlimited to 5G systems or the frequency bands associated therewith, andembodiments of the present disclosure may be utilized in connection withany frequency band. For example, aspects of the present disclosure mayalso be applied to deployment of 5G communication systems, 6G or evenlater releases which may use terahertz (THz) bands.

Depending on the network type, the term ‘base station’ (BS) can refer toany component (or collection of components) configured to providewireless access to a network, such as transmit point (TP),transmit-receive point (TRP), an enhanced base station (eNodeB or eNB),a gNB, a macrocell, a femtocell, a WiFi access point (AP), a satellite,or other wirelessly enabled devices. Base stations may provide wirelessaccess in accordance with one or more wireless communication protocols,e.g., 5G 3GPP New Radio Interface/Access (NR), LTE, LTE advanced(LTE-A), High Speed Packet Access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc.The terms ‘BS,’ ‘gNB,’ and ‘TRP’ can be used interchangeably in thisdisclosure to refer to network infrastructure components that providewireless access to remote terminals. Also, depending on the networktype, the term ‘user equipment’ (UE) can refer to any component such asmobile station, subscriber station, remote terminal, wireless terminal,receive point, vehicle, or user device. For example, a UE could be amobile telephone, a smartphone, a monitoring device, an alarm device, afleet management device, an asset tracking device, an automobile, adesktop computer, an entertainment device, an infotainment device, avending machine, an electricity meter, a water meter, a gas meter, asecurity device, a sensor device, an appliance, and the like.

FIGS. 1-3 below describe various embodiments implemented in wirelesscommunications systems and with the use of orthogonal frequency divisionmultiplexing (OFDM) or orthogonal frequency division multiple access(OFDMA) communication techniques. The descriptions of FIGS. 1-3 are notmeant to imply physical or architectural limitations to the manner inwhich different embodiments may be implemented. Different embodiments ofthe present disclosure may be implemented in any suitably-arrangedcommunications system.

FIG. 1 illustrates an example wireless network 100 according toembodiments of the present disclosure. The embodiment of the wirelessnetwork 100 shown in FIG. 1 is for illustration only. Other embodimentsof the wireless network 100 could be used without departing from thescope of this disclosure.

As shown in FIG. 1 , the wireless network 100 includes a base station,BS 101 (e.g., gNB), a BS 102, and a BS 103. The BS 101 communicates withthe BS 102 and the BS 103. The BS 101 also communicates with at leastone network 130, such as the Internet, a proprietary Internet Protocol(IP) network, or other data network.

The BS 102 provides wireless broadband access to the network 130 for afirst plurality of UEs within a coverage area 120 of the BS 102. Thefirst plurality of UEs includes a UE 111, which may be located in asmall business; a UE 112, which may be located in an enterprise (E); aUE 113, which may be located in a WiFi hotspot (HS); a UE 114, which maybe located in a first residence (R); a UE 115, which may be located in asecond residence (R); and a UE 116, which may be a mobile device (M),such as a cell phone, a wireless laptop, a wireless PDA, or the like.The BS 103 provides wireless broadband access to the network 130 for asecond plurality of UEs within a coverage area 125 of the BS 103. Thesecond plurality of UEs includes the UE 115 and the UE 116. In variousembodiments, a UE 116 may communicate with another UE 115 via asidelink. For example, both UEs 115-116 can be within network coverage(of the same or different base stations). In another example, the UE 116may be within network coverage and the other UE may be outside networkcoverage. In yet another example, both UE are outside network coverage.

In some embodiments, one or more of the BSs 101-103 may communicate witheach other and with the UEs 111-116 using 5G/NR, long term evolution(LTE), long term evolution-advanced (LTE-A), WiMAX, WiFi, or otherwireless communication techniques.

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with BSs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the BSs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programing, or a combination thereof for inter UEcoordination signaling. In certain embodiments, and one or more of theBSs 101-103 includes circuitry, programing, or a combination thereof toallow inter UE coordination signaling.

Although FIG. 1 illustrates one example of a wireless network, variouschanges may be made to FIG. 1 . For example, the wireless network couldinclude any number of BSs and any number of UEs in any suitablearrangement. Also, the BS 101 could communicate directly with any numberof UEs and provide those UEs with wireless broadband access to thenetwork 130. Similarly, each BS 102-103 could communicate directly withthe network 130 and provide UEs with direct wireless broadband access tothe network 130. Further, the BSs 101, 102, and/or 103 could provideaccess to other or additional external networks, such as externaltelephone networks or other types of data networks.

FIG. 2 illustrates an example BS 102 according to embodiments of thepresent disclosure. The embodiment of the BS 102 illustrated in FIG. 2is for illustration only, and the BSs 101 and 103 of FIG. 1 could havethe same or similar configuration. However, BSs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of a BS.

As shown in FIG. 2 , the BS 102 includes multiple antennas 205 a-205 n,multiple radio frequency (RF) transceivers 210 a-210 n, transmit (TX)processing circuitry 215, and receive (RX) processing circuitry 220. TheBS 102 also includes a controller/processor 225, a memory 230, and abackhaul or network interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the wirelessnetwork 100. The RF transceivers 210 a-210 n down-convert the incomingRF signals to generate IF or baseband signals. The IF or basebandsignals are sent to the RX processing circuitry 220, which generatesprocessed baseband signals by filtering, decoding, and/or digitizing thebaseband or IF signals. The RX processing circuitry 220 transmits theprocessed baseband signals to the controller/processor 225 for furtherprocessing.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the BS 102. Forexample, the controller/processor 225 could control the reception ofuplink channel signals and the transmission of downlink channel signalsby the RF transceivers 210 a-210 n, the RX processing circuitry 220, andthe TX processing circuitry 215 in accordance with well-knownprinciples. The controller/processor 225 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 225 could supportinter UE coordination signaling. Any of a wide variety of otherfunctions could be supported in the BS 102 by the controller/processor225. In some embodiments, the controller/processor 225 includes at leastone microprocessor or microcontroller.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the BS 102to communicate with other devices or systems over a backhaul connectionor over a network. The network interface 235 could supportcommunications over any suitable wired or wireless connection(s). Forexample, when the BS 102 is implemented as part of a cellularcommunication system (such as one supporting 5G/NR, LTE, or LTE-A), thenetwork interface 235 could allow the BS 102 to communicate with otherBSs over a wired or wireless backhaul connection. When the BS 102 isimplemented as an access point, the network interface 235 could allowthe BS 102 to communicate over a wired or wireless local area network orover a wired or wireless connection to a larger network (such as theInternet). The network interface 235 includes any suitable structuresupporting communications over a wired or wireless connection, such asan Ethernet or RF transceiver.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a Flash memory or other ROM. In certain embodiments, a pluralityof instructions, such as inter UE coordination signaling is stored inmemory.

Although FIG. 2 illustrates one example of BS 102, various changes maybe made to FIG. 2 . For example, the BS 102 could include any number ofeach component shown in FIG. 2 . As a particular example, an accesspoint could include a number of network interfaces 235, and thecontroller/processor 225 could support routing functions to route databetween different network addresses. As another particular example,while shown as including a single instance of TX processing circuitry215 and a single instance of RX processing circuitry 220, the BS 102could include multiple instances of each (such as one per RFtransceiver). Also, various components in FIG. 2 could be combined,further subdivided, or omitted and additional components could be addedaccording to particular needs.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3 , the UE 116 includes an antenna 305, a RFtransceiver 310, TX processing circuitry 315, a microphone 320, andreceive (RX) processing circuitry 325. The UE 116 also includes aspeaker 330, a processor 340, an input/output (I/O) interface (IF) 345,an input device 350, a display 355, and a memory 360. The memory 360includes an operating system (OS) 361 and one or more applications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by a BS of the wireless network 100 or by another UE.The RF transceiver 310 down-converts the incoming RF signal to generatean intermediate frequency (IF) or baseband signal. The IF or basebandsignal is sent to the RX processing circuitry 325 that generates aprocessed baseband signal by filtering, decoding, and/or digitizing thebaseband or IF signal. The RX processing circuitry 325 transmits theprocessed baseband signal to the speaker 330 (such as for voice data) orto the processor 340 for further processing (such as for web browsingdata).

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of downlink channel signals or sidelinkchannel signals and the transmission of uplink channel signals orslidelink channel signals by the RF transceiver 310, the RX processingcircuitry 325, and the TX processing circuitry 315 in accordance withwell-known principles. In some embodiments, the processor 340 includesat least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for beammanagement and inter-UE coordination. The processor 340 can move datainto or out of the memory 360 as required by an executing process. Insome embodiments, the processor 340 is configured to execute theapplications 362 based on the OS 361 or in response to signals receivedfrom BSs or other UEs or an operator. The processor 340 is also coupledto the I/O interface 345, which provides the UE 116 with the ability toconnect to other devices, such as laptop computers and handheldcomputers. The I/O interface 345 is the communication path between theseaccessories and the processor 340.

The processor 340 is also coupled to the input device 350. The operatorof the UE 116 can use the input device 350 to enter data into the UE116. The input device 350 can be a keyboard, touchscreen, mouse, trackball, voice input, or other device capable of acting as a user interfaceto allow a user in interact with the UE 116. For example, the inputdevice 350 can include voice recognition processing, thereby allowing auser to input a voice command. In another example, the input device 350can include a touch panel, a (digital) pen sensor, a key, or anultrasonic input device. The touch panel can recognize, for example, atouch input in at least one scheme, such as a capacitive scheme, apressure sensitive scheme, an infrared scheme, or an ultrasonic scheme.

The processor 340 is also coupled to the display 355. The display 355may be a liquid crystal display, light emitting diode display, or otherdisplay capable of rendering text and/or at least limited graphics, suchas from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3 . For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

FIG. 4 and FIG. 5 illustrate example wireless transmit and receive pathsaccording to this disclosure. In the following description, a transmitpath 400, of FIG. 4 , may be described as being implemented in a BS(such as the BS 102), while a receive path 500, of FIG. 5 , may bedescribed as being implemented in a UE (such as a UE 116). However, itmay be understood that the receive path 500 can be implemented in a BSand that the transmit path 400 can be implemented in a UE.

The transmit path 400 as illustrated in FIG. 4 includes a channel codingand modulation block 405, a serial-to-parallel (S-to-P) block 410, asize N inverse fast Fourier transform (IFFT) block 415, aparallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425,and an up-converter (UC) 430. The receive path 500 as illustrated inFIG. 5 includes a down-converter (DC) 555, a remove cyclic prefix block560, a serial-to-parallel (S-to-P) block 565, a size N fast Fouriertransform (FFT) block 570, a parallel-to-serial (P-to-S) block 575, anda channel decoding and demodulation block 580.

As illustrated in FIG. 4 , the channel coding and modulation block 405receives a set of information bits, applies coding (such as alow-density parity check (LDPC) coding), and modulates the input bits(such as with quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) to generate a sequence of frequency-domainmodulation symbols. The serial-to-parallel block 410 converts (such asde-multiplexes) the serial modulated symbols to parallel data in orderto generate N parallel symbol streams, where N is the IFFT/FFT size usedin the BS 102 and the UE 116. The size N IFFT block 415 performs an IFFToperation on the N parallel symbol streams to generate time-domainoutput signals. The parallel-to-serial block 420 converts (such asmultiplexes) the parallel time-domain output symbols from the size NIFFT block 415 in order to generate a serial time-domain signal. The addcyclic prefix block 425 inserts a cyclic prefix to the time-domainsignal. The up-converter 430 modulates (such as up-converts) the outputof the add cyclic prefix block 425 to an RF frequency for transmissionvia a wireless channel. The signal may also be filtered at basebandbefore conversion to the RF frequency.

A transmitted RF signal from the BS 102 arrives at the UE 116 afterpassing through the wireless channel, and reverse operations to those atthe BS 102 are performed at the UE 116. Alternatively, for sidelinkoperation, the transmitted RF signal from the UE 115 arrives at the UE116 after passing through the wireless channel, and reverse operationsto those at the UE 115 are performed at the UE 116.

As illustrated in FIG. 5 , the down-converter 555 down-converts thereceived signal to a baseband frequency, and the remove cyclic prefixblock 560 removes the cyclic prefix to generate a serial time-domainbaseband signal. The serial-to-parallel block 565 converts thetime-domain baseband signal to parallel time domain signals. The size NFFT block 570 performs an FFT algorithm to generate N parallelfrequency-domain signals. The parallel-to-serial block 575 converts theparallel frequency-domain signals to a sequence of modulated datasymbols. The channel decoding and demodulation block 580 demodulates anddecodes the modulated symbols to recover the original input data stream.

Each of the BSs 101-103 may implement a transmit path 400 as illustratedin FIG. 4 that is analogous to transmitting in the downlink to UEs111-116 and may implement a receive path 500 as illustrated in FIG. 5that is analogous to receiving in the uplink from UEs 111-116.Similarly, each of UEs 111-116 may implement the transmit path 400 fortransmitting in the uplink to the BSs 101-103, or transmitting in thesidelink to other UEs and may implement the receive path 500 forreceiving in the downlink from the BSs 101-103, or receiving in thesidelink from other UEs.

Each of the components in FIG. 4 and FIG. 5 can be implemented usinghardware or using a combination of hardware and software/firmware. As aparticular example, at least some of the components in FIG. 4 and FIG. 5may be implemented in software, while other components may beimplemented by configurable hardware or a mixture of software andconfigurable hardware. For instance, the FFT block 570 and the IFFTblock 515 may be implemented as configurable software algorithms, wherethe value of size N may be modified according to the implementation.

Furthermore, although described as using FFT and IFFT, this is by way ofillustration only and may not be construed to limit the scope of thisdisclosure. Other types of transforms, such as discrete Fouriertransform (DFT) and inverse discrete Fourier transform (IDFT) functions,can be used. It may be appreciated that the value of the variable N maybe any integer number (such as 1, 2, 3, 4, or the like) for DFT and IDFTfunctions, while the value of the variable N may be any integer numberthat is a power of two (such as 1, 2, 4, 8, 16, or the like) for FFT andIFFT functions.

Although FIG. 4 and FIG. 5 illustrate examples of wireless transmit andreceive paths, various changes may be made to FIG. 4 and FIG. 5 . Forexample, various components in FIG. 4 and FIG. 5 can be combined,further subdivided, or omitted and additional components can be addedaccording to particular needs. Also, FIG. 4 and FIG. 5 are meant toillustrate examples of the types of transmit and receive paths that canbe used in a wireless network. Any other suitable architectures can beused to support wireless communications in a wireless network.

A time unit for (i) downlink (DL) signaling on a cell, (ii) uplink (UL)signaling on a cell, or (iii) sidelink (SL) signaling is one symbol. Asymbol belongs to a slot that includes a number of symbols such as 14symbols. A slot can also be used as a time unit. A bandwidth (BW) unitis referred to as a resource block (RB). One RB includes a number ofsub-carriers (SCs). For example, a slot can have duration of onemillisecond and an RB can have a bandwidth of 180 kHz and include 12 SCswith inter-SC spacing of 15 kHz. For another example, a slot can have aduration of 0.25 milliseconds and include 14 symbols and an RB can havea BW of 720 kHz and include 12 SCs with SC spacing of 60 kHz. An RB inone symbol of a slot is referred to as physical RB (PRB) and includes anumber of resource elements (REs). A slot can be either full DL slot, orfull UL slot, or hybrid slot similar to a special subframe in timedivision duplex (TDD) systems. In addition, a slot can have symbols forSL communications. A UE can configure one or more bandwidth parts (BWPs)of a system BW for transmissions or receptions of signals or channels.Furthermore, slots can be organized in subframes It is noted that asubframe has a time duration of 1 ms. Subframes can be further organizedinto radio frames or simply frames wherein a frame has a duration of 10ms.

SL signals and channels are transmitted and received on sub-channelswithin a resource pool, where a resource pool is a set of time-frequencyresources used for SL transmission and reception within a SL BWP. SLchannels can include physical SL shared channels (PSSCHs) conveying datainformation and second stage/part SL control information (SCI), physicalSL control channels (PSCCHs) conveying first stage/part SCI forscheduling transmissions/receptions of PSSCHs, physical SL feedbackchannels (PSFCHs) conveying hybrid automatic repeat requestacknowledgement (HARQ-ACK) information in response to correct (ACKvalue) or incorrect (NACK value) transport block receptions inrespective PSSCHs, and physical SL Broadcast channel (PSBCH) conveyingsystem information to assist in SL synchronization. SL signals caninclude demodulation reference signals DM-RS that are multiplexed inPSSCH or PSCCH transmissions to assist with data or SCI demodulation,channel state information reference signals (CSI-RS) for channelmeasurements, phase tracking reference signals (PT-RS) for tracking acarrier phase, and SL primary synchronization signals (S-PSS) and SLsecondary synchronization signals (S-SSS) for SL synchronization. SCIcan include two parts/stages corresponding to two respective SCI formatswhere, for example, the first SCI format is multiplexed on a PSCCH andthe second SCI format is multiplexed along with SL data on a PSSCH thatis transmitted in physical resources indicated by the first SCI format.

A SL channel can operate in different cast modes, such as a unicast modea groupcast mode, a broadcast mode, a resource allocation mode, and thelike. In a unicast mode, a PSCCH/PSSCH conveys SL information from oneUE to only one other UE. In a groupcast mode, a PSCCH/PSSCH conveys SLinformation from one UE to a group of UEs within a (pre-) configuredset. In a broadcast mode, a PSCCH/PSSCH conveys SL information from oneUE to all surrounding UEs.

In certain embodiments, there are two resource allocation modes for aPSCCH/PSSCH transmission. In resource allocation mode 1, a gNB (such asthe BS 102) schedules a UE on the SL and conveys scheduling informationto the UE transmitting on the SL through a DCI format. In addition,resource allocation mode 1 supports configurated grant type 1 andconfigured grant type 2. In configured grant type 1, resources areperiodically configured for transmission of SL data. in configurationgrant type 2, a DCI activates transmission on periodically allocatedresources starting with a first PSCCH/PSSCH transmission opportunitywhere the configured sidelink grant was (re-)initialized.

In resource allocation mode 2, a UE (such as the UE 116) schedules a SLtransmission. SL transmissions can operate within network coverage whereeach UE is within the communication range of a gNB, outside networkcoverage where all UEs have no communication with any gNB, or withpartial network coverage, where only some UEs are within thecommunication range of a gNB.

In case of groupcast PSCCH/PSSCH transmission, a network can configure aUE one of two options for reporting of HARQ-ACK information by the UE.In the first HARQ-ACK reporting option, a UE can attempt to decode atransport block (TB) in a PSSCH reception. For example, the UE candetect a SCI format scheduling the TB reception through a correspondingPSSCH. If the UE fails to correctly decode the TB, the UE multiplexes anegative acknowledgement (NACK) in a PSFCH transmission. In this option,the UE does not transmit a PSFCH with a positive acknowledgment (ACK)when the UE correctly decodes the TB

In the second option, a UE (such as the UE 116) can attempt to decode aTB if, for example, the UE detects a SCI format that schedules acorresponding PSSCH. If the UE correctly decodes the TB, the UEmultiplexes an ACK in a PSFCH transmission. Otherwise, if the UE doesnot correctly decode the TB, the UE multiplexes a NACK in a PSFCHtransmission.

In HARQ-ACK reporting option one above, when a UE (such as the UE 116)that transmitted the PSSCH detects a NACK in a PSFCH reception, the UEcan transmit another PSSCH with the TB (retransmission of the TB). InHARQ-ACK reporting option two above, when a UE that transmitted thePSSCH does not detect an ACK in a PSFCH reception, such as when the UEdetects a NACK or does not detect a PSFCH reception, the UE can transmitanother PSSCH with the TB.

A sidelink resource pool includes a set/pool of slots and a set/pool ofRBs used for sidelink transmission and sidelink reception. A set ofslots which belong to a sidelink resource pool can be denoted byEquation (1) and can be configured, for example, at least using abitmap. In Equation (1), below, T′_(max) is the number of SL slots in aresource pool. Within each slot

t^(′)_(y)^(SL)of a sidelink resource pool, there are N_(subCH) contiguous sub-channelsin the frequency domain for sidelink transmission, where N_(subCH) isprovided by a higher-layer parameter. Subchannel m, where m is between 0and N_(subCH)−1, is given by a set of n_(subCHsize) contiguous PRBs,given by Equation (2). In Equation (2), below, j=0, 1, . . . ,n_(subCHsize)−1, n_(subCHstart) and n_(subCHsize) are provided by higherlayer parameters.

$\begin{matrix}\left\{ {t_{0}^{\prime SL},\ t_{1}^{\prime SL},\ t_{2}^{\prime SL},{.\;.\;.}\;,t_{{T^{\prime}}_{{MAX}^{- 1}}}^{\prime SL}} \right\} & (1) \\{n_{PRB} = {n_{subCHstart} + {m \cdot n_{subCHsize}} + j}} & (2)\end{matrix}$

In certain embodiments, the slots of a SL resource pool are determinedas follows. First, a set of slots that may belong to a resource bedenoted by Equation (1), above, where 0≤t_(i) ^(SL)<10240, and0≤T<T_(max). The slot index is relative to slot #0 of SFN #0 of theserving cell, or DFN #0. The set slot includes all slots exceptN_(S-SSB) slots that are configured for SL SS/PBCH Block (S-SSB). Theset slot also does not include N nonSL slots where at least one SLsymbols is not not-semi-statically configured as UL symbol by higherlayer parameter tdd-UL-DL-ConfigurationCommon or sl-TDD-Configuration.In a SL slots, OFDM symbols Y-th, (Y+1)-th, . . . , (Y+X−1)-th are SLsymbols, where Y is determined by the higher layer parametersl-StartSymbol and X is determined by higher layer parametersl-LengthSymbols. Additionally, the set slot also does not includeN_(reserved) reserved slots, e.g., these slots are excluded from theresource pool. Reserved slots are determined such that the slots in theset {t₀ ^(SL), t₁ ^(SL), t₂ ^(SL), . . . , t_(T) _(MAX) ₋₁ ^(SL)} is amultiple of the bitmap length (L_(bitmap)), where the bitmap (b₀, b₁, .. . , b_(L) _(bitmap) ₋₁) is configured by higher layers.

It is noted that the reserved bits are determined based on {l₀, l₁, . .. , l₂ _(λ) _(×10240-N) _(S-SSB) _(-N) _(nonSL) ₋₁} and the set of slotsare in the range 0 . . . 2^(μ)×10240−1, excluding S-SSB slots and non-SLslots. The slots are arranged in ascending order of the slot index. Thenumber of reserved slots, excluded from the resource pool, is given byEquation (6). The reserved slots l_(r) are given by Equation (7).T_(max) is described in Equation (8).

$\begin{matrix}{N_{reserved} = {\left( {{2^{\mu} \times 10240} - N_{S - {SSB}} - N_{nonSL}} \right){mod}\mspace{14mu}{L_{bitmap}.}}} & (6) \\{{r = \left\lfloor \frac{m \cdot \left( {{2^{\mu} \times 10240} - N_{S - {SSB}} - N_{nonSL}} \right)}{N_{reserved}} \right\rfloor},{{{where}\mspace{14mu} m} = 0},1,{.\;.\;.}\;,N_{reserved}} & (7) \\{T_{\max} = {{2^{\mu} \times 10240} - N_{S - {SSB}} - N_{nonSL} - {N_{reserved}.}}} & (8)\end{matrix}$

In certain embodiments, the slots are arranged in ascending order ofslot index.

For resource (re-)selection or re-evaluation in slot n, a UE candetermine a set of available single-slot resources for transmissionwithin a resource selection window [n+T₁, n+T₂], such that a single-slotresource for transmission, R_(x,y) is defined as a set of L_(subCH)contiguous subchannels x+i, where i=0, 1, . . . , L_(subCH)−1 in slott_(y) ^(SL). T₁ is determined by the UE such that, 0≤T₁≤T_(proc,1)^(SL), where T_(proc,1) ^(SL) is a PSSCH processing time. T₂ isdetermined by the UE such that T_(2min)≤T₂≤Remaining Packet DelayBudget, as long as T_(2min)<Remaining Packet Delay Budget, else T₂ isequal to the Remaining Packet Delay Budget. T_(2min) is a configured byhigher layers and depends on the priority of the SL transmission.

In certain embodiments, the resource (re-)selection is a two-stepprocedure. The first step is based on sensing and resource exclusion,which is to identify the candidate resources within a resource selectionwindow. Wherein, sensing includes decoding first stage/part SCI andmeasuring SL RSRP, wherein the SL RSRP can measured on PSCCH DMRS orPSSCH DMRS. Candidate resources are resources that belong to a resourcepool, but exclude resources that were previously reserved, orpotentially reserved by other UEs. The resources excluded are based onfirst stage/part SCIs decoded in a sensing window and for which the UEmeasures a SL reference signal receive power (RSRP) that exceeds athreshold. The threshold depends on the priority indicated in a SCIformat and on the priority of the SL transmission. The resourcesexcluded are based on reserved transmissions or semi-persistenttransmissions that can collide with the excluded resources or any ofreserved or semi-persistent transmissions. The second step includesselecting or re-selecting a resource from the identified candidateresources.

A resource pool can be configured by higher layer parametersl-MultiReserveResource, to allow reservation of a sidelink resource foran initial transmission of a Transport Block (TB), by an SCI associatedwith a different TB based on sensing and resource selection procedure.The set of possible reservation periods is provided by higher layerparameter sl-ResourceReservePeriodList.

It is noted that during the first step of the resource (re-)selectionprocedure described above, a UE can monitor slots in a sensing window[n−T₀, n−T_(proc,0)), where the UE monitors slots belonging to acorresponding sidelink resource pool that are not used for the UE's owntransmission. Sensing includes: decoding the first stage/part SCI onPSCCH and measuring the SL RSRP, wherein the SL RSRP can be measured onthe PSCCH DMRS or the PSSCH DMRS. To determine a candidate single-slotresource set to report to higher layers, a UE excludes, the following,from the set of available single-slot resources for SL transmissionwithin a resource pool and within a resource selection window. The UEcan exclude a single slot resource R_(x,y), such that for any slot t_(m)^(SL) not monitored within the sensing window with a hypotheticalreceived SCI Format 1-0, with a “Resource reservation period” set to anyperiodicity value allowed by a higher layer parametersl-ResourceReservePeriodList, and indicating all sub-channels of theresource pool in this slot, satisfies condition below. The UE can alsoexclude single slot resource R_(x,y), such that for any received SCIwithin the sensing window. The associated L1-RSRP measurement is above a(pre-)configured SL-RSRP threshold, where the SL-RSRP threshold dependson the priority indicated in the received SCI and that of the SLtransmission for which resources are being selected. The conditiondescribes that the received SCI in slot t_(m) ^(SL) or if “Resourcereservation field” is present in the received SCI the same SCI isassumed to be received in slot t_(m+q×P′) _(rsvp_Rx) ^(SL), indicates aset of resource blocks that overlaps R_(x,y+j×P′) _(rsvp_Tx) . It isnoted that q=1, 2, . . . , Q when Equation (3) is satisfied. OtherwiseQ=1.

$\begin{matrix}{\left. {P_{rsvp\_ RX} \leq {{T_{scal}\mspace{14mu}{and}\mspace{14mu} n^{\prime}} - m} < P_{rsvp\_ Rx}^{\prime}}\rightarrow Q \right. = {{\left\lceil \frac{T_{scal}}{P_{r{svp\_ RX}}} \right\rceil \cdot T_{scal}}\mspace{14mu}{is}\mspace{14mu} T_{2}\mspace{14mu}{in}\mspace{14mu}{units}\mspace{14mu}{of}\mspace{14mu}{mill}\text{i-s}{econds}}} & (3)\end{matrix}$Additionally, if n belongs to (t′₀ ^(SL), t′₁ ^(SL), . . . , t′_(T′)_(max) ₋₁ ^(SL)), then n′=n, otherwise n′ is the first slot after slot nbelonging to set (t′₀ ^(SL), t′₁ ^(SL), . . . , t′_(T′) _(max) ₋₁^(SL)). Moreover, j=0, 1, . . . C_(resel)−1. P_(rsvp_RX) is theindicated resource reservation period in the received SCI in physicalslots, P′_(rsvp_Rx) is that value converted to logical slots asdescribed later in this disclosure, and P′_(rsvp_Tx) is the resourcereservation period of the SL transmissions for which resources are beingreserved in logical slots.

If the candidate resources are less than a (pre-)configured percentage(such as 20% of the total available resources within the resourceselection window), then the (pre-) configured SL-RSRP thresholds areincreased by a predetermined amount, such as 3 dB.

NR sidelink introduced two new procedures for mode 2 resourceallocation; re-evaluation and pre-emption check.

Regarding the re-evaluation check, the re-evaluation check occurs when aUE (such as the UE 116) checks the availability of pre-selected SLresources before the resources are first signaled in an SCI Format, andif needed re-selects new SL resources. For a pre-selected resource to befirst-time signaled in slot m, the UE performs a re-evaluation check atleast in slot m−T₃. The re-evaluation check includes performing thefirst step of the SL resource selection procedure, which involvesidentifying a candidate (available) sidelink resource set in a resourceselection window as previously described. The re-evaluation check alsoincludes that if the pre-selected resource is available in the candidatesidelink resource set, then the resource is used/signaled for sidelinktransmission. Otherwise, the pre-selected resource is not available inthe candidate sidelink resource set, a new sidelink resource isre-selected from the candidate sidelink resource set.

Regarding the pre-emption check, the pre-emption check occurs when a UE(such as the UE 116) checks the availability of pre-selected SLresources that have been previously signaled and reserved in an SCIFormat, and if needed re-selects new SL resources. For a pre-selectedand reserved resource to be signaled in slot m, the UE performs apre-emption check at least in slot m−T₃. When pre-emption check isenabled by higher layers, pre-emption check can include the followingexamples. For example, the pre-emption check can include performing thefirst step of the SL resource selection procedure, which involvesidentifying candidate (available) sidelink resource set in a resourceselection window as previously described. Additionally, if thepre-selected and reserved resource is available in the candidatesidelink resource set, then the resource is used/signaled for sidelinktransmission, otherwise the pre-selected and reserved resource is notavailable in the candidate sidelink resource set. The resource isexcluded from the candidate resource set due to an SCI, associated witha priority value P_(RX), having a SL RSRP exceeding a threshold, whereinthe SL RSRP is based on one of PSCCH DMRS or PSSCH DMRS. Let thepriority value of the sidelink resource being checked for pre-emption beP_(TX). Moreover, if the priority value P_(RX) is less than ahigher-layer configured threshold and the priority value P_(RX) is lessthan the priority value P_(TX). The pre-selected and reserved sidelinkresource is pre-empted. A new sidelink resource is re-selected from thecandidate sidelink resource set. Note that, a lower priority valueindicates traffic of higher priority. Otherwise, the resource isused/signaled for sidelink transmission.

It is noted that the 3GPP Release 16 is the first NR release to includesidelink through work item “5G V2X with NR sidelink.” The mechanismsintroduced focused mainly on vehicle-to-everything (V2X) and can be usedfor public safety when the service requirement can be met. Release 17extends sidelink support to more use cases through work item “NRSidelink enhancement.” One of the motivations for the sidelinkenhancement in Release 17, is power savings. For example, the powersavings enables UEs with battery constraint to perform sidelinkoperations in a power efficient manner. Rel-16 NR sidelink is designedbased on the assumption of “always-on” when UE operates sidelink, e.g.,only focusing on UEs installed in vehicles with sufficient batterycapacity. Solutions for power saving in Rel-17 are required forvulnerable road users (VRUs) in V2X use cases and for UEs in publicsafety and commercial use cases where power consumption in the UEs needsto be minimized.

One of the objectives of the Release 17 sidelink enhancement work item,is to specify resource allocation enhancements that reduce powerconsumption, taking the principle of the release 14 LTE sidelink randomresource selection and partial sensing as baseline with potentialenhancements. For example, resource allocation enhancements can includespecifying resource allocation to reduce power consumption of the UEs[RAN1, RAN2]. The baseline is to introduce the principle of Rel-14 LTEsidelink random resource selection and partial sensing to Rel-16 NRsidelink resource allocation mode 2. It is noted that taking Rel-14 asthe baseline does not preclude introducing a new solution to reducepower consumption for the cases where the baseline cannot work properly.

Another motivation for the sidelink enhancement includes enhancedreliability and reduced latency. Enhanced reliability and reducedlatency allow the support of URLLC-type sidelink use cases in wideroperation scenarios. The system level reliability and latencyperformance of sidelink is affected by the communication conditions suchas the wireless channel status and the offered load, and Rel-16 NRsidelink is expected to have limitation in achieving high reliabilityand low latency in some conditions, e.g., when the channel is relativelybusy. Solutions that can enhance reliability and reduce latency arerequired in order to keep providing the use cases requiring low latencyand high reliability under such communication conditions.

For yet another objective of the release 17 sidelink enhancement is tostudy the feasibility and benefits of enhancements to resourceallocation mode 2, wherein a set of resources can be determined at UE-Aand sent to UE-B, and UE-B takes into account this set for its owntransmission. For example, the study the feasibility and benefit of theenhancement(s) in mode 2 for enhanced reliability and reduced latencyand specify the identified solution if deemed feasible and beneficial.For instance, a set of resources is determined at UE-A. This set is sentto UE-B in mode 2, and UE-B takes this into account in the resourceselection for its own transmission.

Embodiments of the present disclosure take into consideration that, theUE transmitting sidelink information (e.g., UE-B) is not aware of thesidelink environment at the UE receiving the sidelink information(UE-A), without receiving sidelink resource selection assistanceinformation (i.e., inter-UE co-ordination information) from UE-A. Forexample, the hidden node problem is when a third UE or node is causinginterference or is attempting to transmit to UE-A at the same time thatUE-B is attempting to transmit to UE-A, but is not discerned by UE-B.When UE-A provides resource selection assistance information to UE-B, itcan assist UE-B in making resource allocation decisions that avoid thehidden node problem when transmitting to UE-A. In another example, theexposed node problem is when a sidelink resource is being sensed asoccupied at UE-B, i.e., the UE transmitting the sidelink information,but is not being sensed as occupied at UE-A, i.e., the UE receiving thesidelink information. If UE-B were to only use its sensing informationit would not transmit on the resource to UE-A. However, if UE-B getsresource selection assistance information from UE-A, UE-B can allocatethe resource for sidelink transmission to UE-A. Resource selectionassistance information, for example, can be whether a SL resource ispreferred or not for SL transmission.

Additionally, embodiments of the present disclosure take intoconsideration that the UE transmitting sidelink information (e.g., UE-B)is not aware whether the intended receiver UE of the sidelinkinformation is receiving or transmitting at the time of transmissionfrom UE-B without receiving sidelink resource selection assistanceinformation (i.e., inter-UE co-ordination information) from UE-A. Forexample, the half-duplex problem occurs when a first UE is transmittinginformation on a sidelink to a second UE at a time (i.e., in a slotand/or a symbol), when the second UE is transmitting, and the second UEis unable to receive the SL transmission of the first UE. Resourceselection assistance information, for example, can be whether a SLresource is preferred or not for SL transmission, and can at least bedetermined partially on whether a SL resource can be received by asecond UE.

As described in U.S. application Ser. No. 17/139,908 filed on Dec. 31,2020, which is incorporated by reference in its entirety, a first UE(s)can transmit a pre-indication of its intention to transmit or resourcereservation on a SL resource to a second UE(s). The second UE(s) cangrant or trigger the SL transmission of the first UE(s). Embodiments ofthe present disclosure describe the signaling aspects of thepre-indication or resource reservation from a first UE(s) (e.g.,UE-B(s)) to a second UE(s) (e.g., UE-A(s)). Embodiments of the presentdisclosure describe the signaling aspects of the grant or triggeringfrom the second UE(s) (e.g., UE-A(s)) to the first UE(s) (e.g.,UE-B(s)), wherein the grant or trigger can indicate preferred ornon-preferred SL resources.

As discussed above, 3GPP Release 16 includes sidelink through work item“5G V2X with NR sidelink,” the mechanisms introduced focused mainly onvehicle-to-everything (V2X) and can be used for public safety when theservice requirement can be met. Release 17 extends sidelink support tomore use cases through work item “NR Sidelink enhancement”. One of themotivations for the sidelink enhancement, in Release 17, is enhancedreliability and reduced latency. One of the objectives of the Release 17sidelink enhancement is to study the feasibility and benefit of inter-UEcoordination by having a set of resources determined at UE-A indicatedto a UE-B, and UE-B takes into account this information for its SLtransmission.

Embodiments of this disclosure describe that the set of resourcesdetermined at a UE-A (such as UE 116) can be based on resources from oneor more UE-Bs (such as UE 116) that can potentially overlap and collidefor example due to the hidden node problem. Alternatively, oradditionally the set of resources can be based on UE-A's own sensing.Alternatively, or additionally the set of resources can be based onUE-A's intended transmissions for example to avoid the half-duplexproblem. UE-A can indicate to the one or more UE-Bs whether thedetermined SL resources are preferred or non-preferred. Non-preferredresources are resources that have a collision or conflict with anotherSL or UL transmission.

Embodiments of this disclosure introduces signaling and methods forpre-indication or reservation of a SL transmission on a SL resource.Additionally, embodiments of this disclosure introduces signaling andmethods for granting or triggering a transmission on a SL resource, suchas by an indication of preferred and/or non-preferred resources.Non-preferred resources are resources that have a collision or conflictwith another SL or UL transmission.

Embodiments of the present disclosure define UE-B as an SL UEtransmitting SL information on a SL resource. The network can includeone or more UE-B Embodiments of the present disclosure define UE-A as aSL-UE that is the intended receiver of a SL transmission from a UE-B.Alternatively, UE-A can be any other SL UE in the network.

In this discourse a PSFCH channel used for signaling (e.g., signalingpre-indicated or reserved resources, or signalingpreferred/non-preferred resources or resources with or without conflict)is a PSFCH-like channel or a feedback channel. A PSFCH-like channel or afeedback channel is a physical channel with same structure as that ofPSFCH (as described in 38.211), i.e., the Physical channel can include12 orthogonal sequences multiplexed into one PRB. Each one or twosequences is used to convey one bit of information. The PSFCH has aduration of two symbols, the first symbol is a repetition of the secondsymbol.

FIG. 6 illustrates an example SL network 600 according to embodiments ofpresent disclosure. The SL network 600 includes 3 SL UEs, that of UE-A,UE-B1, and UE-B2. It is noted that there can be additional SL UEs in thenetwork. As illustrated in the SL network 600 the UE-A, UE-B1, and UE-B2are capable of receiving and transmitting on the SL air interface. It isnoted that UE-A, UE-B1, and UE-B2 can be similar to any of the UEs ofFIG. 1 and include similar components to that of the UE 116. There aretwo UE-Bs, (i.e., UE-B1 and UE-B2) with data to transmit on the SLinterface, and there is one UE-A. The UE-A can be the intended receiverof the UE-B1 and UE-B2 transmissions, or just the intended receiver ofthe UE-B1 or UE-B2 transmissions, or any other SL UE in the network.

In step one, according to FIG. 6 , a UE-B indicates its intention totransmit on a future SL resource. The following examples and embodimentsdescribe step 1.

For example (example 0.1.1), a UE-B indicates its intention to transmiton a future SL resource or reserves a future SL resource using aPSFCH-like transmission or a feedback channel.

For another example (example 0.1.2), a UE-B indicates its intention totransmit on a future SL resource or reserves a future SL resource usinga PSCCH transmission. For instance, the PSCCH can include resourceindication for a current sub-frame as well as reserved resources for afuture sub-frame, wherein the reserved resource(s) can be for aretransmission of the current transmission (if needed or if applicable)and/or the reserved resource(s) can be for a new transmission. Foranother instance, the PSCCH transmission, can be a PSCCH transmissionwith no PSSCH transmission in the current subframe, and only includesresources reserved in future subframe. Please refer to component 2 formore details.

For yet another example (example 0.1.3), a UE-B indicates its intentionto transmit on future SL resource or reserves a future SL resource usinga newly defined physical channel.

For another example (example 0.1.4), a UE-B indicates its intention totransmit on future SL resource or reserves a future SL resource usingsecond stage/part SCI on PSSCH.

For another example (example 0.1.5), a UE-B indicates its intention totransmit on future SL resource or reserves a future SL resource using SLshared channel on PSSCH.

For another example (example 0.1.6), a UE-B indicates its intention totransmit on future SL resource or reserves a future SL resource using SLMAC CE.

In step two, according to FIG. 6 , a UE-A after receiving pre-indicationor resource reservation of a future SL transmission from one or moreUE-B(s), determines if an overlap (full overlap or partial overall) or acollision can occur on a future SL resource. Thereafter the UE-Aconsequently, grant or trigger a SL transmission on a SL resource from aUE-B, i.e., UE-A determines the availability or non-availability (incase of a conflict) of the resources indicated or reserved by UE-B. Thecollision or overlap in time and frequency domains of a pre-indicated orreserved SL resource can be with another pre-indicated or reserved SLresource at UE-A. Additionally or alternatively, the collision oroverlap in time and frequency domains of a pre-indicated or reserved SLresource can be with a SL resource based on the sensing at UE-A.Additionally or alternatively, the collision or overlap of apre-indicated or reserved SL resource can be with SL resource used byUE-A for its SL transmission, the overlap in this case can be in timedomain. The grant or triggering of a SL transmission on a SL resourcecan be based on indication of preferred and/or non-preferred SLresources. Non-preferred resources are resources that have a collisionor conflict with another SL or UL transmission. The following examplesand embodiments describe step 2.

For example (example 0.2.1), a UE-A grants or triggers a SL transmissionon a SL resource using a PSFCH-like transmission or a feedback channel.Please refer to component 1 for more details.

For another example (example 0.2.2), a UE-A grants or triggers a SLtransmission on a SL resource using a PSCCH transmission. Please referto component 2 for more details.

For another example (example 0.2.3), a UE-A grants or triggers a SLtransmission on a SL resource using a newly defined physical channel.

For another example (example 0.2.4), a UE-A grants or triggers a SLtransmission on a SL resource using second stage/part SCI on PSSCH.

For another example (example 0.2.5), a UE-A grants or triggers a SLtransmission on a SL resource using SL shared channel on PSSCH.

For yet another example (example 0.2.6), a UE-A grants or triggers a SLtransmission on a SL resource using SL MAC CE.

In step three, after a UE-B receives a grant or trigger signal,indicating a preferred or non-preferred resource for a UE-B, the UE-Bcan determine whether or not to proceed with a SL transmission on apre-indicated or reserved SL resource. Non-preferred resources areresources that have a collision or conflict with another SL or ULtransmission. If the reserved resource is indicated to have a conflict,UE-B performs resource re-selection to select a new resource for SLtransmission.

FIG. 7 illustrates a timeline 700 for a SL transmission on a future SLresource according to embodiments of present disclosure. FIGS. 8 and 9illustrate example methods 800 and 900 for a user equipment (UE)according to embodiments of present disclosure. The steps of the method800 and 900 can be performed by any of the UEs 111-116 of FIG. 1 , suchas the UE 116 of FIG. 3 . The methods 800 and 900 of FIGS. 8 and 9 arefor illustration only and other embodiments can be used withoutdeparting from the scope of the present disclosure.

The timeline 700 of FIG. 7 is for pre-indication/reservation andgrant/trigger for a SL transmission on a future SL resource. The method800 of FIG. 8 describes the procedure for UE-A while the method 900 ofFIG. 9 describes a procedure for UE-B.

In step one, UE-B(s) select resources available for SL transmission,e.g. set A, for example this can be based on sensing performed atUE-B(s) and/or based on earlier inter-UE co-ordination informationreceived at UE-B(s). UE-B(s) (e.g., UE-B1 and UE-B2) transmit apre-indication/reservation signal of intention to transmit on a futureSL resource (e.g., resource SL1, or set B) (step 902) and the UE-A(s)receive the pre-indication/reservation signal transmitted by UE-B(s)(step 802). Wherein set B can be set A or a subset of set A. This signalcan include N resources. N is the size (cardinality) of set B.

Regarding step 902 (UE-B transmit a pre-indication/reservation signal),the pre-indication/reservation signal is similar to release 16 SLtransmission. For example, a SL transmission includes a PSCCH+PSSCH with1^(st) stage/part SCI in PSCCH, 2^(nd) stage part/SCI and SL sharedchannel in PSSCH. The 1^(st) stage/part includes resources for thecurrent transmission and up to 2 reserved resources for SL HARQre-transmissions (e.g., N=1 or N=2)).

for another example, the pre-indication/reservation signal is similar torelease 16 SL transmission, wherein a SL transmission includes aPSCCH+PSSCH with Pt stage/part SCI in PSCCH, 2^(nd) stage part/SCI andSL shared channel in PSSCH. The 1^(st) stage/part includes resources forthe current transmission and up to N reserved resources for SLtransmissions. Wherein, the SL transmission can be a re-transmission ofthe same SL TB, or a transmission of new SL TB. In one example N=1. Inone example, N=2. In another example, N is larger than 2 and specifiedin the system specification and/or pre-configured and/or configured orupdated by RRC signaling and/or MAC CE signaling and/or L1 controlsignaling.

For yet another example, the pre-indication/reservation signal can be(i) a standalone first stage/part SCI, i.e., PSCCH without PSSCH, (ii)included in a second (or first) part/stage SCI with or without SL sharedchannel in the PSSCH, i.e., 1^(st) stage/part SCI+2^(nd) stage/part withSL shared channel, or Pt stage/part SCI+2^(nd) stage/part with SL sharedchannel, and the pre-indication/reservation signal is included in Ptstage/part SCI or 2^(nd) stage/part, (iii) a PSFCH like signal, (iv) aSL MAC CE, (v) a PC5 RRC, (vi) or a combination thereof. Thepre-indication/reservation signal can include N reserved resources.

Step two is preformed after UE-A(s) performs inter-UE coordination basedon the received pre-indication/reservation signal from one or multipleUE-B(s), wherein the received signal from a UE-B can include Npre-indicated/reserved SL resources. N can be the same or different foreach UE-B. UE-A(s) determines preferred or non-preferred resource out ofthe N resources for each UE-B (see step 804). Non-preferred resourcesare resources that have a collision or conflict with another SL or ULtransmission. For example, this can be based on a determination ofoverlap of a first pre-indicated or reserved SL resource with a secondSL resource. The second SL resource can be (i) a pre-indicated orreserved resource of another UE, wherein overlap can be in time andfrequency, (ii) based on sensing performed at UE-A, wherein overlap canbe in time and frequency, (iii) a SL resource used for transmission fromUE-A, in this case overlap can be in time domain.

Additionally, the second SL resource can be a SL resource that overlapswith an UL transmission such as (i) physical random access channel(PRACH) preamble for Type 1 and Type 2 Random access procedure, (ii)physical uplink shared channel (PUSCH) for Type 2 Random accessprocedure, (iii) message 3 RACH resources, (iv) physical uplink controlchannel (PUCCH) transmissions including UCI for the UE interface and/orSL HARQ-ACK feedback to network, (v) dynamically scheduled PUSCHtransmission, (vi) configured grant Type 1 or Type 2 PUSCH transmission,(vii) SRS transmissions (periodic, semi-persistent and aperiodic), or(viii) the conflict (i.e., whether the resource is non-preferred or not)can be further determined based on the priority of the UL transmissionand the priority of the SL transmission.

The second SL resource can be an NR SL resources that overlaps with anLTE SL transmission or reception. The conflict (i.e., whether theresource is non-preferred or not) can be further determined based on thepriority of the LTE SL transmission or reception and the priority of theNR SL transmission.

UE-A can determine a preferred SL transmission on an overlapped orcollided SL resource based on prioritization. Additionally, UE-Adetermines a preferred or non-preferred (a non-preferred SL resource isa SL resource with a detected conflict) SL resource based on theSL-RSRP, wherein the SL-RSRP can be measured using the PSCCH DMRS or thePSSCH DMRS. If a SL resource pre-indicate/reserved by UE-B overlaps orpartially overlaps, in time and frequency domains, with a SL resourcedetected at UE-A (e.g., based on sensing at UE-A) and if; (1) MeasuredSL RSRP of the resource causing conflict is larger than (or larger thanor equal to) the SL RSRP threshold. The SL resourcepre-indicated/reserved by UE-B is in conflict, (2) Measured SL RSRP ofthe resource causing conflict is less than or equal to (or less than)the SL RSRP threshold. The SL resource pre-indicated/reserved by UE-B isnot in conflict. Wherein, the SL RSRP threshold can depend on one ormore of; (1) priority of UE-B's transmission, priority of theoverlapping SL resource at UE-A. For example, the UE-A(s) transmits agrant/trigger signal indicating preferred and/or non-preferred resourcesto UE-B(s) (e.g., UE-B1 and UE-B2). For example, the preferred and/ornon-preferred resources (resources with a conflict) can be for the setof N pre-indicated/reserved resources from UE-B. For another example,UE-A(s) transmits a grant/trigger signal indicating preferred and/ornon-preferred resources to UE-B(s) (e.g., UE-B1 and UE-B2). For example,the preferred (e.g., without a conflict) and/or non-preferred resources(resources with a conflict) can be for the set of pre-indicated/reservedresources from UE-B. In one example, the absence of a signal indicatingresources with conflict from UE-A at UE-B, indicates to UE-B that thereis no conflict in the set of pre-indicated/reserved resources.

In step three the UE-B(s) (e.g., UE-B1 and UE-B2) determine whether toproceed or not with a SL transmission on a SL resource (see step 906).For example, if a pre-indicated/reserved resource is indicated as notbeing in conflict (e.g., preferred or available), SL transmission canproceed on such resource). If, UE-B(s) (e.g., UE-B1 and UE-B2) do nottransmit on pre-indicated resources a new SL resource can be selectedand/or reserved and/or pre-indicated for SL transmission by performingSL resource (re-) selection based on sensing performed at UE-B(s) and/orbased on earlier inter-UE co-ordination information received at UE-B(s).

The method 800 of FIG. 8 and the method 900 of FIG. 9 describe the abovethree steps. For example, the method 800 is directed towards UE-A whilethe method 900 is directed towards the UE-B.

As illustrated in FIG. 8 , in step 802 UE-A receives thepre-indication/reservation signal transmitted by UE(B). In step 804, theUE-A performs inter-UE coordination based on the receivedpre-indication/reservation signal of the one or more UE-B(s) (of steps802 and 902), a UE-A sensing and UE-A SL transmission, and the like. Forexample, a UE-A determines preferred or non-preferred (conflict)resource for each UE-B. In step 806, UE-A transmits a grant/triggerindicating preferred and/or non-preferred resource to UE-B.

As illustrated in FIG. 9 , in step 902, the UE-B transmits apre-indication/reservation signal of intention to transmit on a futureSL resource. In step 904, the UE-B receives a grant/trigger signal fromUE-A (see step 806). In step 906, the UE-B determines whether to proceedwith a SL transmission on a SL resource. In step 908, if the UE-B doesnot transmit on pre-indicated resources due to conflict, a new SLresource can be selected, reserved, pre-indicated, or a combinationthereof for SL transmission.

Although FIGS. 8 and 9 illustrate the methods 800 and 900, respectively,various changes may be made to FIGS. 8 and 9 . For example, while themethod 800 of FIG. 8 and the method 900 of FIG. 9 are shown as a seriesof steps, various steps could overlap, occur in parallel, occur in adifferent order, or occur multiple times. In another example, steps maybe omitted or replaced by other steps. For example, steps of the method800 can be executed in a different order.

Embodiments of the present disclosure describe a component 1 for PSFCHlike pre-indication/reservation and grand/trigger signaling. Thefollowing examples and embodiments describe PSFCH likepre-indication/reservation and grand/trigger signaling.

In certain embodiments, the pre-indication/reservation signal can be a1-bit signal per UE-B. A PSFCH-like channel or signal can be used forthe pre-indication/reservation signal. A PSFCH-like channel can transmittwo-logical values, e.g., logical 0 and logical 1. For example (example1.1.1), the pre-indication/reservation of a SL transmission in a futureSL resource can be indicated by one logical level of PSFCH (e.g.,logical 1), and the absence of SL transmission in a future SL resourcecan be indicated by the other logical level of PSFCH (e.g., logical 0).For another example (example 1.1.2), the pre-indication/reservation of aSL transmission in a future SL resource can be indicated by atransmission of a PSFCH-like channel, and the absence of SL transmissionin a future SL resource can be indicated by no transmission (i.e.,discontinuous transmission (DTX)) of a PSFCH-like channel.

In certain embodiments, the grant/trigger signal can be a 1-bit signalper UE-B. A PSFCH-like (or feedback) channel or signal can be used forgrant/trigger signal. A PSFCH-like (or feedback) channel can transmittwo-logical values, e.g., logical 0 and logical 1. For example (example1.2.1), the grant/trigger signal of a SL transmission in a SL resourcecan be indicated by one logical level of PSFCH (e.g., logical 1) whenthe SL transmission in that resource is preferred, and by the otherlogical level of PSFCH (e.g., logical 0) when SL transmission in thatresource is not preferred. For another example (example 1.2.2), thegrant/trigger signal of a SL transmission in a SL resource can beindicated by a transmission of a PSFCH-like (or feedback) channel whenthe SL transmission in that resource is preferred and can be indicatedby no transmission (i.e., DTX) of a PSFCH-like (or feedback) channelwhen SL transmission in that resource is not preferred. For anotherexample (example 1.2.3), the grant/trigger signal of a SL transmissionin a SL resource can be indicated by no transmission (i.e., DTX) of aPSFCH-like (or feedback) channel when the SL transmission in thatresource is preferred (e.g., no conflict detected), and can be indicatedby a transmission of a PSFCH-like (or feedback) channel when SLtransmission in that resource is not preferred (e.g., conflictdetected).

For example (example 1.3.1), the SL slots can be partitioned intoseparate resource pools for SL data and for SL signaling. It is notedthat SL data resource pool can be used to convey PSCCH, PSSCH and PSFCHtransmissions and can have a slot structure similar to the structure ofNR release 16 SL slot. SL signaling resource pool can be used to conveysignaling information such as pre-indication/reservation singling andgrant/trigger signaling.

FIG. 10 illustrates an example diagram 1000 of separate resource poolsfor SL data transmission and SL signaling according to embodiments ofpresent disclosure. The diagram 1000 illustrates an example of separateresource pools for SL data transmission and SL signaling. In thisexample, the resource pools have a bitmap of size L_(bitmap)=10, wherein2 slots are allocated to the signaling resource pool and 8 slots areallocated to the SL data resource pool.

The slot structure of the signaling resource pool can be such that, forone example (example 1.3.1.1), a SL slot can containpre-indication/reservation singling and grant/trigger signaling, asillustrated in FIG. 10 . The slot structure of the signaling resourcepool can be such that, for one example (example 1.3.1.2), a SL slot cancontain either pre-indication/reservation singling or grant/triggersignaling.

In one example, a PSFCH-like transmission or feedback channel includesan OFDM symbol, preceded by a duplicate of that OFDM symbol, andfollowed by a gap OFDM symbol. In general, a SL slot can be divided intoM groups of K OFDM symbols, with each group of K OFDM symbols separatedby a gap OFDM, with a gap OFDM symbol at the end of the SL slot. In oneexample, K can be 2 OFDM symbols for a PSFCH-like transmission orfeedback channel, which includes the duplicate OFDM symbols and thePSFCH-like OFDM symbol. In one example, with 14 symbols in a SL slot, Mcan be 4 as illustrated in FIG. 10 .

As discussed above in example 1.3.1.1, the M groups of OFDM symbols perslot can be used for pre-indication/reservation signaling as well asgrant/trigger signaling, i.e., M=M₁+M₂, wherein M₁ OFDM symbol groupsare for pre-indication/reservation signaling and M₂ OFDM symbol groupsare for grant/trigger signaling. For the example as illustrated in FIG.10 , M=4, M₁=2 and M₂=2.

As discussed above in example 1.3.1.2, the M groups of OFDM symbols perslot can be used for either pre-indication/reservation signaling orgrant/trigger signaling, i.e., M=M₁=M₂, wherein M₁ OFDM symbol groupsare for pre-indication/reservation signaling and M₂ OFDM symbol groupsare for grant/trigger signaling.

For each sub-channel of a slot of a SL data resource pool, two bits canexist in the corresponding sub-channel of the signaling resource pool.One bit can be for pre-indication/reservation signaling of thecorresponding sub-channel and a second bit can be for grant/triggersignaling of the corresponding sub-channel, for each UE-B.

The number of signals that can be indicated by a slot of a signalingresource pool is described in Equation (4), below.

$\begin{matrix}{M \times N_{subCH} \times N_{subCHsize} \times L} & (4)\end{matrix}$Here, M is the number of OFDM symbol groups for PSFCH-like transmissionsor feedback channel. Additionally, N_(subCH) is the number ofsub-channels in a SL resource pool. N_(subCHsize) is the size of thesub-channel in PRBs. L is the number of PSFCH-like resources in one PRBof a group of K symbols. For example L can equal 6, e.g., when there are12 cyclic shifts in a PRB, and 2 cyclic shifts are allocated to eachresource, e.g., one cyclic shift for logical 0, and the other cyclicshift for logical 1.

According to example 1.3.1.1, described above, the number of signalsrequired for pre-indication/reservation signaling as well grant/triggersignaling for a group of N_(UEB) UE-B s is described in Equation (5),below.

$\begin{matrix}{2\left( {{For}\mspace{14mu}{{pre\_ indication}/{reseravtion}}\mspace{14mu}{as}\mspace{14mu}{well}\mspace{14mu}{as}\mspace{14mu}{{grant}/{trigger}}\mspace{14mu}{signaling}} \right) \times N_{subCH} \times N_{SLData} \times N_{UEB}} & (5)\end{matrix}$Where, N_(SLData) is the number of SL slots of a SL data resource poolassociated with a signaling slot. N_(UEB) is the number of UEs that cantransmit/receive pre_indication/reservation and/or grant/triggersignaling.

The mapping of signaling resources to SL slots of a SL data resourcepool and UE-B(s) can be performed within each sub-channel as indicatedin FIG. 11 . There are various ways to determine the order of mappingsignaling resources to SL slots of a SL data resource pool and UE-B(s).

FIG. 11 illustrates an example mapping diagram 1100 for mappingsignaling resources to SL slots of a SL data resource pool according toembodiments of present disclosure.

In one example, according to the example of FIG. 11 , the mapping orderfor SL resources of a slot of a signaling resource pool is in order ofFirst in increasing order of resource within a PRB of a group of K OFDMsymbols. Then in increasing order of PRB within a group of K OFDMsymbols. Finally, in increasing order (in time) of a group of K OFDMsymbols.

The mapping of SL slots of a SL data resource pool associated with asignaling slot and UE-B(s) can be according to the following example. Inthis example, The first M₁ group of K OFDM symbols can be allocated topre-indication/reservation signaling, and the last M₂ group of K OFDMsymbols can be allocated to grant/trigger signaling. Within each groupthe order can be, first, in increasing order of UE-B index, and second,in increasing order of SL slot index within the SL slots of a SL dataresource pool associated with a signaling slot.

As illustrated, FIG. 11 is a mapping example with M=4, M₁=2, M₂=2,N_(subChsize)=10, L=6 and N_(UEB)=30.

For example (example 1.3.2), the SL slots of SL resource pool can beused for both SL signaling as well as SL data transmission.

In certain embodiments, a UE-B can receive the grant/trigger signalingintended to that UE-B, a UE-B could also receive the grant/triggersignaling of other UE-Bs, and take that into account when making adecision on transmission on a SL resource.

Embodiments of the present disclosure describe a component 2 for PSCCHpre-indication/reservation and grand/trigger signaling. The followingexamples and embodiments describe PSCCH pre-indication/reservation andgrand/trigger signaling.

The pre-indication/reservation signal can be included in PSCCHtransmission. For example (example 2.1.1), the PSCCH transmission isassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates the SL resources of the SL transmission onPSSCH in the current SL slot as well SL resources reserved in a futureSL slot, wherein the reserved resource(s) can be for a retransmission ofthe current transmission (if needed or if applicable) and/or thereserved resource(s) can be for a new transmission. For example, thenumber of SL resources reserved is N. In one example N=1, in anotherexample N=2, in yet another example N>2 and is specified in systemspecifications and/or configured or updated by RRC signaling and/or MACCE signaling and/or L1 control signaling.

For another example (example 2.1.2), the PSCCH transmission is notassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates SL resources reserved in a future SL slot.For example, the number of SL resources reserved is N. In one exampleN=1, in another example N=2, in yet another example N>2 and is specifiedin system specifications and/or configured or updated by RRC signalingand/or MAC CE signaling and/or L1 control signaling.

The grant/trigger signal can be included in PSCCH or PSSCH transmissionfrom UE-A(s) to UE-B(s). For example (example 2.2.1), a PSCCHtransmission is not associated with a PSSCH transmission in a same SLslot. The PSCCH includes SCI that indicates SL resources, previouslypre-indicated or reserved, granted/triggered for a SL transmission(preferred SL resources).

For another example (example 2.2.2), a PSCCH transmission is notassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates SL resources, previously pre-indicated orreserved, not preferred for SL transmission.

For another example (example 2.2.3), a PSSCH transmission (SL data or SLMAC CE or second stage SCI) includes the grant/trigger signaling. ThePSSCH transmission indicates SL resources, previously pre-indicated orreserved, granted/triggered for a SL transmission (preferred SLresources).

For another example (example 2.2.4), a PSSCH transmission (SL data or SLMAC CE or second stage SCI) includes the grant/trigger signaling. ThePSSCH indicates SL resources, previously pre-indicated or reserved, notpreferred for SL transmission.

For another example (example 2.2.5), a PSCCH transmission can beassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates SL resources, previously pre-indicated orreserved, granted/triggered for a SL transmission (preferred SLresources).

For yet another example (example 2.2.6), a PSCCH transmission can beassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates SL resources, previously pre-indicated orreserved, not preferred for SL transmission.

For yet another example (example 2.2.7), the granted/triggered resourcesare conveyed in an N-bit bitmap, with one-bit corresponding to each oneof the N per-indicated/reserved SL resources. If aper-indicated/reserved SL resource has no conflict (e.g., preferred oravailable) a logical level is set for the corresponding bit (e.g.,logical level 1 or logical level 0). If a per-indicated/reserved SLresource has conflict (e.g., non-preferred or not available) a differentlogical level is set for the corresponding bit (e.g., logical level 0 orlogical level 1).

FIG. 12 illustrates an example signaling diagram 1200 using physicalsidelink control channel (PSCCH) according to embodiments of presentdisclosure. In particular, FIG. 12 illustrates an examplepre-indication/reservation signaling and grant/trigger signaling usingPSCCH. In this example, there are two UE-Bs. UE-B1 and UE-B1pre-indicate or reserve a future SL resource for SL transmission usingPSCCH. The UE-A can be the intended receiver of the UE-B1 and UE-B2transmissions, or just the intended receiver of the UE-B1 or UE-B2transmissions. UE-A performs inter-UE coordination, if the SL resourcesindicated by UE-B1 and UE-B2 overlap in time and frequency domains(partially and/or fully) or collide, UE-A can indicate usinggrant/triggering signaling whether the SL resource is preferred or notpreferred to each UE-B. For example, the reserved SL resource of UE-B1can be indicated as preferred and the reserved SL resource of UE-B2 canbe indicated as non-preferred or vice versa. Additionally oralternatively, the collision or overlap in time and frequency domains ofa pre-indicated or reserved SL resource can be with a SL resource basedon the sensing at UE-A (e.g., checking whether a resource is reserveddue to a decoded SCI with a SL RSRP that exceeds a threshold), whereinUE-A can indicate using grant/triggering signaling whether the SLresource is preferred or not preferred to each UE-B. A conflict due tosensing can take into account the SL RSRP of the SL resources involvedin the collision for determining whether a pre-indicated/reserved SLresource from UE-B has a conflict, as described earlier in thisdisclosure. A conflict determination can also take into account thepriority levels of the SL transmissions associated with the SL resourcesinvolved in the collision. Additionally or alternatively, the collisionor overlap of a pre-indicated or reserved SL resource can be with SLresource used by UE-A for its SL transmission, the overlap in this casecan just be in time domain, wherein UE-A can indicate usinggrant/triggering signaling whether the SL resource is preferred or notpreferred to each UE-B. When UE-B(s) decides transmission on reserved SLresource, it can take this signaling into account.

In certain embodiments, a UE-B can receive the grant/trigger signalingintended to that UE-B, a UE-B could also receive the grant/triggersignaling of other UE-B s, and take that into account when making adecision on transmission on a SL resource. UE-B selects apre-indicated/reserved SL resource that has no conflict indicated fromUE-A. If there is no pre-indicated/reserved SL resource UE-B preformsresource (re-)selection to select a SL resource taking into account itsown sensing results and/or any inter-UE coordination information fromother UEs.

Embodiments of the present disclosure describe a component 3 for mixedPSFCH-like (or feedback channel) and PSCCH pre-indication/reservationand grant/trigger signaling. The following examples and embodimentsdescribe mixed PSFCH-like (or feedback channel) and PSCCHpre-indication/reservation and grant/trigger signaling.

In this component (component 3), pre-indication/reservation signalingcan be included in a PSCCH transmission, and grant/trigger signaling canbe included in a PSFCH-like transmission or feedback channel.Alternatively, pre-indication/reservation signaling can be included in aPSFCH-like transmission or feedback channel, and grant/trigger signalingcan be included in a PSSCH transmission.

For example (example 3.1), the pre-indication/reservation signal can beincluded in PSCCH transmission, and the grant/trigger signaling can beincluded in a PSFCH-like transmission or feedback channel. UE-Bpre-indicates/reserves N SL resources using PSCCH. UE-A indicatesconflicting SL resources and/or available SL resource usinggrant/trigger signaling. That is (example 3.1.1), the PSCCH transmissionis associated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates the SL resources of the SL transmission onPSSCH in the current SL slot as well N SL resources reserved in a futureSL slot, wherein the reserved resource(s) can be for a retransmission ofthe current transmission (if needed or if applicable) and/or thereserved resource(s) can be for a new transmission.

For instance (example 3.1.1.1), a UE-A transmits HARQ-ACK feedback onPSFCH in response to a PSCCH/PSSCH transmission in a SL slot, and thepre-indicated/reserved resource can be for a retransmission of thecurrent transmission. A UE-A can transmit positive acknowledgment (ACK)on PSFCH if the PSSCH transmission is successfully decoded. If the PSSCHtransmission is not successfully decoded, a UE-B can retransmit on apre-indicated/reserved resource if UE-A determines that it is available.

If UE-A determines that the pre-indicated or reserved SL resource doesnot overlap or collide in time and frequency domains with a second SLtransmission, or if the pre-indicated or reserved SL resource collidesor overlaps in time and frequency domains with a second SL transmission,but has the highest priority and/or the highest SL RSRP and/or SL RSRPabove a threshold, wherein a second SL transmission can be determinedfrom a pre-indication/reserved signal(s) received by UE-A and/or UE-A'ssensing information and/or UE-A's own SL transmission (with overlap intime with the pre-indicated/reserved resource of UE-B). A conflict dueto sensing can take into account the SL RSRP of the SL resourcesinvolved in the collision for determining whether apre-indicated/reserved SL resource from UE-B has a conflict, asdescribed earlier in this disclosure. UE-A can indicate to UE-B anegative acknowledgement (NACK) for retransmission and indicate to UE-Bthat the pre-indicated/reserved resource is preferred for SLtransmission, e.g., that the pre-indicated/reserved resource has noconflict.

Alternatively, If UE-A determines that the pre-indicated or reserved SLresource collides or overlaps in time and frequency domains with anotherSL transmission, but has a lower priority and/or lower SL RSRP than anyof the colliding SL transmissions and/or SL RSRP below a threshold,wherein a colliding SL transmission can be determined from apre-indication/reserved signal(s) received by UE-A and/or UE-A's sensinginformation and/or UE-A's own SL transmission (with overlap in time withthe pre-indicated/reserved resource of UE-B). UE-A can indicate to UE-Ba negative acknowledgement (NACK) for retransmission and indicate toUE-B that the pre-indicated/reserved resource is not preferred (e.g.,has a conflict) for SL transmission. UE-B can reselect a differentresource for SL transmission based on its own sensing and/or inter-UEco-ordination information from other UEs.

If the pre-indication/reservation signal from UE-B to UE-A includes morethan one (e.g., N, with N>1) resource, UE-A can determine a singleoutcome for that status of the N pre-indicated/reserved resource.According to one of the following; (1) If any resourcepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (allpre-indicated/configured SL resources have no conflict) UE-A indicatesto UE-B resources have no conflict (e.g., preferred). (2) If allpre-indicated/configured SL resources have a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (at least onepre-indicated/configured SL resource has no conflict) UE-A indicates toUE-B resources have no conflict (e.g., preferred). (3) If first in-timepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (firstin-time pre-indicated/configured SL resource has no conflict) UE-Aindicates to UE-B resources have no conflict (e.g., preferred).

In this example (example, 3.1.1.1) the PSFCH-like (or feedback) channelor signal can indicate one of three levels, that of (i) ACK forsuccessful reception of PSSCH, (ii) NACK (failed reception of PSSCH) andtransmission on pre-indicated/reserved resource(s) is preferred (e.g.,no conflict detected on reserved resource), or (iii) NACK (failedreception of PSSCH) and transmission on pre-indicated/reservedresource(s) is not preferred (e.g., with conflict detected on reservedresource).

In certain embodiments (denoted as Option 1), for a PSFCH with threelevels, 2-bit PSFCH, e.g., a PSFCH design with 4 cyclic shifts allocatedto each resource. In this case, a PSFCH design with 3 cyclic shiftsallocated to each resource is also feasible, as there are three levelsto be indicated.

FIGS. 13A-13F illustrate example PSFCH-like signaling or feedbackchannel according to embodiments of present disclosure.

FIG. 13A illustrates a PSFCH signaling design 1300 a, e.g., for unicastHARQ-ACK feedback and Groupcast HARQ-ACK reporting option (2), whereinfor a two-bit PSFCH resource m_(cs)=6 indicates ACK, m_(cs)=0, indicatesNACK with retransmission on reserved resource preferred (e.g., noconflict detected on reserved resource), and m_(cs)=3, indicates a NACKwith retransmission on reserved resource not preferred (e.g., conflictdetected on reserved resource) (m_(cs)=9 can be used instead ofm_(cs)=3).

In a variant of FIG. 13A, the cyclic shifts used can be m_(cs)=0 forNACK with preferred resource (i.e., no conflict detected on reservedresource), m_(cs)=4 for NACK with non-preferred resource (i.e., conflictdetected on reserved resource) and m_(cs)=8 for ACK.

FIG. 13B illustrates a PSFCH signaling design 1300 b, e.g., for unicastHARQ-ACK feedback and Groupcast HARQ-ACK reporting option (2), whereinfor a two-bit PSFCH resource m_(cs)=6 indicates ACK, m_(cs)=9, indicatesNACK with retransmission on reserved resource preferred (e.g., noconflict detected on reserved resource), and m_(cs)=3, indicates a NACKwith retransmission on reserved resource not preferred (e.g., conflictdetected on reserved resource) (the role of m_(cs)=9 and m_(cs)=3 can beswitched). m_(cs)=0 can be used by UEs not implementing the schemedescribed in example 3.1 to indicate a NACK, this allows co-existence ofolder UEs not implementing this scheme and newer UEs implementing thescheme described in example 3.1, above.

FIG. 13C illustrates a PSFCH signaling design 1300 c, e.g., forGroupcast HARQ-ACK reporting option (1), wherein for a two-bit PSFCHresource m_(cs)=0, indicates NACK with retransmission on reservedresource preferred (e.g., no conflict detected on reserved resource),and m_(cs)=3, indicates a NACK with retransmission on reserved resourcenot preferred (e.g., no conflict detected on reserved resource)(m_(cs)=9 can be used instead of m_(cs)=3). There is no ACK feedbackwith Groupcast HARQ-ACK reporting option (1).

In a variant of FIG. 13C, the cyclic shifts used can be m_(cs)=0 forNACK with preferred resource (e.g., no conflict detected on reservedresource), m_(cs)=6 for NACK with non-preferred resource (e.g., conflictdetected on reserved resource).

FIG. 13D illustrates a PSFCH signaling design 1300 d, e.g., forGroupcast HARQ-ACK reporting option (1), wherein for a two-bit PSFCHresource m_(cs)=9, indicates NACK with retransmission on reservedresource preferred (e.g., no conflict detected on reserved resource),and m_(cs)=3, indicates a NACK with retransmission on reserved resourcenot preferred (e.g., conflict detected on reserved resource) (the roleof m_(cs)=9 and m_(cs)=3 can be switched). m_(cs)=0 can be used by UEsnot implementing the scheme described in example 3.1 to indicate a NACK,this allows co-existence of older UEs not implementing this scheme andnewer UEs implementing the scheme described in example 3.1. There is noACK feedback with Groupcast HARQ-ACK reporting option (1).

In certain embodiments (denoted as option 2), 2 1-bit PSFCH (or feedbackchannel) resources are allocated to a UE.

A first PSFCH resource can indicate the HARQ-ACK feedback. This resourcecan be common with UEs not implementing the scheme described in example3.1. A second PSFCH resource can be used to indicate whether a reservedresource is preferred (e.g., no conflict detected on reserved resource)or not (e.g., conflict detected on reserved resource) for apre-indicated/reserved SL resource. For example, logical 1 one canindicate that a reserved resource is preferred (e.g., no conflictdetected on reserved resource), and logical 0 can indicate that areserved resource is not preferred (e.g., conflict detected on reservedresource), or vice versa. Option 2 includes the following sub-options.

A first sub-option is denoted as Option 2-1 (e.g., for Unicast andGroupcast HARQ-ACK reporting option (2)). In case of ACK, indicate ACKon the first PSFCH resource, no transmission on the second PSFCH-like(feedback channel) resource. In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), indicateNACK on the first resource, and indicate reserved resource is preferredon the second resource. In case of NACK and reserved resource is notpreferred (e.g., conflict detected on reserved resource), indicate NACKon the first resource, and indicate reserved resource is not preferredon the second resource. This option requires 2 PSFCH transmissionsand/or feedback channels in case of NACK. This scheme can be extended toindicate the conflict status for each of N pre-indicated/reserved SLresources by having a PSFCH-like (feedback channel) for eachpre-indicated/reserved SL resource in addition to the PSFCH for HARQ-ACKstatus. Therefore, there can be a total of N+1 PSFCH (and/or feedbackchannel) resources. Alternatively, the conflict status for the Npre-indicated/reserved SL resources can be indicated using a singlePSFCH-like (feedback channel) resource conveying one bit as describedearlier, in this case only 2 PSFCH (and/or feedback channel) resourcesare needed. Alternatively, the N PSFCHes (feedback channels) can bereplaced by one PSFCH-like (feedback channel) carrying N bits.

A second sub-option is noted as Option 2-2 (e.g., for Unicast andGroupcast HARQ-ACK reporting option (2)). In case of ACK, indicate ACKon the first PSFCH resource, no transmission on the second PSFCH-like(feedback channel) resource. In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), notransmission on the first resource (DTX), and indicate reserved resourceis preferred on the second resource. In case of NACK and reservedresource is not preferred, no transmission on the first resource (DTX),and indicate reserved resource is not preferred on the second resource(i.e., conflict detected on reserved resource). This option requires 1PSFCH (and/or feedback channel) transmission in all cases. A UE notimplementing this scheme and receiving PSFCH (feedback channel)transmissions, when it receives DTX on the first PSFCH resource from aUE implementing this scheme indicating a NACK, interprets the DTX asNACK and retransmits. A UE implementing this scheme and receiving PSFCHtransmissions and/or feedback channels, when it receives a NACK from aUE not implementing this scheme on a first PSFCH resource can retransmiton a reserved resource, a UE not implementing this scheme andtransmitting PSFCH does not check if the pre-indicated/reserved resourceis preferred or not. This scheme can be extended to indicate theconflict status for each of N pre-indicated/reserved SL resources byhaving a PSFCH-like (or feedback channel) for eachpre-indicated/reserved SL resource in addition to the PSFCH for HARQ-ACKstatus. Therefore, there can be a total of N+1 PSFCH (and/or feedbackchannel) resources. Alternatively, the conflict status for the of Npre-indicated/reserved SL resources can be indicated using a singlePSFCH (or feedback channel) resource conveying one bit as describedearlier, in this case only 2 PSFCH (and/or feedback channel) resourcesare needed. In case of ACK only one PSFCH is transmitted in case of NACKN PSFCHes (feedback channels) are transmitted. Alternatively, the NPSFCHes can be replaced by one PSFCH-like (feedback channel) carrying Nbits.

A third sub-option is noted as Option 2-3 (e.g., for Unicast andGroupcast HARQ-ACK reporting option (2)). In case of ACK, indicate ACKon the first PSFCH resource, no transmission on the second PSFCH(feedback channel) resource. In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), indicateNACK on the first resource, this also indicates that the reservedresource is preferred, no transmission on the second resource. In caseof NACK and reserved resource is not preferred (e.g., conflict detectedon reserved resource), no transmission on the first resource (DTX), andindicate reserved resource is not preferred on the second resource. Thisoption requires 1 PSFCH (or feedback channel) transmission in all cases.A UE not implementing this scheme and receiving PSFCH transmissions,when it receives DTX on the first PSFCH resource from a UE implementingthis scheme indicating a NACK and reserved resources not preferred,interprets the DTX as NACK and retransmits. A UE implementing thisscheme and receiving PSFCH transmissions, when it receives a NACK from aUE not implementing this scheme on a first PSFCH resource can retransmiton a reserved resource, a UE not implementing this scheme andtransmitting PSFCH does not check if the pre-indicated/reserved resourceis preferred or not.

It is noted that in option 2-2, a UE implementing this scheme andreceiving a NACK on the first PSFCH resource, will be able to determinethat the NACK is from a UE not implementing the scheme described inexample 3.1, and can perform additional evaluation on the reservedresource, while in option 2-3, a UE implementing this scheme andreceiving a NACK on the first PSFCH resource, will not know if this isfrom a UE implementing the scheme described in example 3.1 or not.

A fourth sub-option is noted as Option 2-4 (single PSFCH resource)(e.g., for Unicast and Groupcast HARQ-ACK reporting option (2)). In caseof ACK, indicate ACK on the first PSFCH resource, no transmission on thesecond PSFCH resource. In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), indicateNACK on the first resource, this also indicates that the reservedresource is preferred, no transmission on the second resource. In caseof NACK and reserved resource is not preferred (e.g., conflict detectedon reserved resource), no transmission on the first resource (DTX), notransmission on second resource. This option requires 1 PSFCH resourcewith no more than one PSFCH transmission in all cases. A UE notimplementing this scheme and receiving PSFCH transmissions, when itreceives DTX on the first PSFCH resource from a UE implementing thisscheme indicating a NACK and reserved resources not preferred,interprets the DTX as NACK and retransmits. A UE implementing thisscheme and receiving PSFCH transmissions, when it receives a NACK from aUE not implementing this scheme on a first PSFCH resource can retransmiton a reserved resource, a UE not implementing this scheme andtransmitting PSFCH does not check if the pre-indicated/reserved resourceis preferred or not. A UE implementing this scheme and receiving PSFCHtransmissions, when it receives DTX on the first PSFCH resource, itcould assume that the DTX is an indication of a non-preferredpre-indicated/reserved resource (e.g., a resource that has a collisionor conflict), however, it will not be able to distinguish a DTX due to anon-preferred pre-indicated/reserved resource from a DTX due to a UEthat should have transmitted a PSFCH and did not transmit the PSFCH dueto non-reception of a corresponding PSCCH.

A fifth sub-option is noted as Option 2-5 (e.g., for Groupcast HARQ-ACKreporting option (1)). In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), indicateNACK on the first resource, and indicate reserved resource is preferredon the second resource. In case of NACK and reserved resource is notpreferred (e.g., conflict detected on reserved resource), indicate NACKon the first resource, and indicate reserved resource is not preferredon the second resource. This option requires 2 PSFCH (and/or feedbackchannel) transmissions in case of NACK. There is no ACK feedback withGroupcast HARQ-ACK reporting option (1). In this option, a UEimplementing this scheme that receives a PSFCH on a first resource withNACK, and does not receive a PSFCH (feedback channel) on a secondresource, can be an indication that the NACK on the first PSFCH resourceis from a UE not implementing this scheme, additional evaluation can bedone before retransmitting on the pre-indicated/reserved resource. A UEimplementing this scheme that receives a PSFCH on a first resource withNACK, and receives a second PSFCH (feedback) indicating preferred ornon-preferred pre-indicated/reserved resources (e.g., a resource thathas a collision or conflict), if any UE indicates non-preferredpre-indicated/reserved resource a UE receiving the indication canre-selected a different SL resource (e.g., based on that UE's sensingand/or inter-UE coordination information from other UEs), otherwise theUE receiving the indication can use reserved resource. This scheme canbe extended to indicate the conflict status for each of Npre-indicated/reserved SL resources by having a PSFCH (feedback channel)for each pre-indicated/reserved SL resource in addition to the PSFCH forHARQ-ACK status. Therefore, there can be a total of N+1 PSFCH (and/orfeedback channel) resources. Alternatively, the conflict status for theof N pre-indicated/reserved SL resources can be indicated using a singlePSFCH (feedback channel) resource conveying one bit as describedearlier, in this case only 2 PSFCH (and/or feedback channel) resourcesare needed. Alternatively, the N PSFCHes (feedback channels) can bereplaced by one PSFCH (feedback channel) carrying N bits.

A sixth sub-option is noted as Option 2-6 (e.g. for Groupcast HARQ-ACKreporting option (1)). In case of NACK and reserved resource ispreferred (e.g., no conflict detected on reserved resource), indicateNACK on the first resource, this also indicates that the reservedresource is preferred, no transmission on the second resource. In caseof NACK and reserved resource is not preferred (e.g., conflict detectedon reserved resource), no transmission on the first resource (DTX), andindicate reserved resource is not preferred on the second resource. Thisoption requires 1 PSFCH transmission in case of NACK. There is no ACKfeedback with Groupcast HARQ-ACK reporting option (1).

In case of Groupcast HARQ-ACK Feedback, the PSFCH resource indicatingpreferred (e.g., no conflict detected on reserved resource) ornon-preferred pre-indicated/reserved resource (e.g., a resource that hasa collision or conflict) can be in a first example UE specific, or itcan be in a second example UE-common (i.e., one resource for all UEs inthe groupcast set). When the UE is transmitting feedback to indicatepreferred (e.g., no conflict detected on reserved resource) ornon-preferred (e.g., conflict detected on reserved resource)pre-indicated/reserved resource, it can in a first example transmit alogical level for a preferred pre-indicated/reserved resource andtransmit a second logical level for non-preferred pre-indicated/reservedresource; or in a second example it can transmit a signal for apreferred pre-indicated/reserved resource and no transmission (DTX) fornon-preferred pre-indicated/reserved resource; or in a third example itcan transmit a signal for a non-preferred pre-indicated/reservedresource and no transmission (DTX) for a preferredpre-indicated/reserved resource.

In certain embodiments (denoted as Option 3), a PSFCH has 2 cyclicshifts. For indication of value 1, a transmit occurs on first cyclicshift only. For indication of value 2, a transmit occurs on secondcyclic shift only. For indication of value 3, a transmit on occurs bothcyclic shifts.

For example (example 3.1.1.2), a UE-A transmits HARQ-ACK feedback onPSFCH in response to a PSCCH/PSSCH transmission in a SL slot, and thepre-indicated/reserved resource can be for a retransmission of thecurrent transmission and/or a new transmission. A UE-A can transmitpositive acknowledgment (ACK) on PSFCH if the PSSCH transmission issuccessfully decoded. A UE-A can transmit negative acknowledgment (NACK)on PSFCH if the PSSCH transmission is not successfully decoded. UE-A cantransmit an additional indication whether a pre-indicated/reservedresource is available (e.g., no conflict detected on reserved resource)or not available (e.g., conflict detected on reserved resource).

It is noted that if UE-A determines that the pre-indicated or reservedSL resource does not overlap or collide in time and frequency domainswith a second SL transmission, or if the pre-indicated or reserved SLresource collides or overlaps in time and frequency domains with asecond SL transmission, but has the highest priority and/or the highestSL RSRP and/or SL RSRP above a threshold, wherein a second SLtransmission can be determined from a pre-indication/reserved signal(s)received by UE-A and/or UE-A's sensing information and/or UE-A's own SLtransmission (with overlap in time with the pre-indicated/reservedresource of UE-B). A conflict due to sensing can take into account theSL RSRP of the SL resources involved in the collision for determiningwhether a pre-indicated/reserved SL resource from UE-B has a conflict,as described earlier in this disclosure. UE-A can indicate to UE-B thatthe pre-indicated/reserved resource is preferred for SL transmission,e.g., that the pre-indicated/reserved resource has no conflict.

Alternatively, if UE-A determines that the pre-indicated or reserved SLresource collides or overlaps in time and frequency domains with anotherSL transmission, but has a lower priority and/or lower SL RSRP than anyof the colliding SL transmissions and/or SL RSRP below a threshold,wherein a colliding SL transmission can be determined from apre-indication/reserved signal(s) received by UE-A and/or UE-A's sensinginformation and/or UE-A's own SL transmission (with overlap in time withthe pre-indicated/reserved resource of UE-B). UE-A can indicate to UE-Bthat the pre-indicated/reserved resource is not preferred (e.g., has adetected conflict) for SL transmission. UE-B can reselect a differentresource for SL transmission based on its own sensing and/or inter-UEco-ordination information from other UEs.

If the pre-indication/reservation signal from UE-B to UE-A includes morethan one (e.g., N, with N>1) resource, UE-A can determine a singleoutcome for that status of the N pre-indicated/reserved resource.According to one of the following. (1) If any resourcepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (allpre-indicated/configured SL resources have no conflict) UE-A indicatesto UE-B resources have no conflict (e.g., preferred). (2) If allpre-indicated/configured SL resources have a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (at least onepre-indicated/configured SL resource has no conflict) UE-A indicates toUE-B resources have no conflict (e.g., preferred). (3) If first in-timepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (firstin-time pre-indicated/configured SL resource has no conflict) UE-Aindicates to UE-B resources have no conflict (e.g., preferred).

In this example, the PSFCH-like (or feedback) channel or signal canindicate one of four levels: (i) ACK for successful reception of PSSCHand transmission on pre-indicated/reserved resource is preferred (e.g.,no conflict detected on reserved resource), (ii) ACK for successfulreception of PSSCH and transmission on pre-indicated/reserved resourceis not preferred (e.g., conflict detected on reserved resource), (iii)NACK (failed reception of PSSCH) and transmission onpre-indicated/reserved resource is preferred (e.g., no conflict detectedon reserved resource), and (iv) NACK (failed reception of PSSCH) andtransmission on pre-indicated/reserved resource is not preferred (e.g.,conflict detected on reserved resource).

For a PSFCH with four levels the following options can be considered,such as Option 1, described above (2-bit PSFCH, e.g., a PSFCH designwith 4 cyclic shifts allocated to each resource).

FIG. 13E illustrates a PSFCH-like (feedback channel) signaling design1300 e, e.g., for unicast HARQ-ACK feedback and Groupcast HARQ-ACKreporting option (2), wherein for a two-bit PSFCH resource m_(cs)=6indicates ACK with retransmission on reserved resource preferred (e.g.,no conflict detected on reserved resource), m_(cs)=0, indicates NACKwith retransmission on reserved resource preferred (e.g., no conflictdetected on reserved resource), m_(cs)=9, indicates an ACK withretransmission on reserved resource not preferred (e.g., conflictdetected on reserved resource), m_(cs)=3, indicates a NACK withretransmission on reserved resource not preferred (e.g., conflictdetected on reserved resource) (the role of m_(cs)=9 and m_(cs)=3 can beswitched).

FIG. 13F illustrates a PSFCH signaling design 1300 f, e.g., forGroupcast HARQ-ACK reporting option (1), wherein for a two-bit PSFCHresource m_(cs)=0, indicates NACK with retransmission on reservedresource preferred (e.g., no conflict detected on reserved resource),m_(cs)=⁹, indicates an ACK with retransmission on reserved resource notpreferred (e.g., conflict detected on reserved resource), and m_(cs)=3,indicates a NACK with retransmission on reserved resource not preferred(e.g., conflict detected on reserved resource) (m_(cs)=9 can be usedinstead of m_(cs)=3). There is no ACK feedback withpre-indicated/reserved resources preferred with Groupcast HARQ-ACKreporting option (1).

In certain embodiments (denoted as option 2), 2 1-bit PSFCH resourcesare allocated to a UE.

A first PSFCH resource can indicate the HARQ-ACK feedback. This resourcecan be common with UEs not implementing the scheme described in example3.1. A second PSFCH (feedback channel) resource can be used to indicatewhether a reserved resource is preferred (e.g., no conflict detected onreserved resource) or not (e.g., conflict detected on reserved resource)for a pre-indicated/reserved SL resource. For example, logical 1 one canindicate that a reserved resource is preferred (e.g., no conflictdetected on reserved resource), and logical 0 can indicate that areserved resource is not preferred (e.g., conflict detected on reservedresource), or vice versa. Option 2 includes the following sub-options.

A first sub-option is denoted as Option 2-1 (e.g., for Unicast andGroupcast HARQ-ACK reporting option (2)). In case of ACK and reservedresource is preferred (e.g., no conflict detected on reserved resource),indicate ACK on the first PSFCH resource, and indicate reserved resourceis preferred on the second resource. In case of ACK and reservedresource is not preferred (e.g., conflict detected on reservedresource), indicate ACK on the first PSFCH resource, and indicatereserved resource is not preferred on the second resource. In case ofNACK and reserved resource is preferred (e.g., no conflict detected onreserved resource), indicate NACK on the first resource, and indicatereserved resource is preferred on the second resource. In case of NACKand reserved resource is not preferred (e.g., conflict detected onreserved resource), indicate NACK on the first resource, and indicatereserved resource is not preferred on the second resource. This optionrequires 2 PSFCH (and/or feedback channel) transmissions. This schemecan be extended to indicate the conflict status for each of Npre-indicated/reserved SL resources by having a PSFCH (feedback channel)for each pre-indicated/reserved SL resource in addition to the PSFCH forHARQ-ACK status. Therefore, there can be a total of N+1 PSFCH (and/orfeedback channel) resources. Alternatively, the conflict status for theof N pre-indicated/reserved SL resources can be indicated using a singlePSFCH (feedback channel) resource conveying one bit as describedearlier, in this case only 2 PSFCH (and/or feedback channel) resourcesare needed. Alternatively, the N PSFCHes (feedback channels) can bereplaced by one PSFCH (feedback channel) carrying N bits.

A second sub-option is noted as Option 2-2 (e.g., for Unicast andGroupcast HARQ-ACK reporting option (2)). In case of ACK and reservedresource is preferred (e.g., no conflict detected on reserved resource),indicate ACK on the first PSFCH resource, no transmission on the secondPSFCH resource. In case of ACK and reserved resource is not preferred(e.g., conflict detected on reserved resource), indicate ACK on thesecond PSFCH resource, no transmission on the first PSFCH resource. Incase of NACK and reserved resource is preferred (e.g., no conflictdetected on reserved resource), indicate NACK on the first PSFCHresource, no transmission on the second PSFCH resource. In case of NACKand reserved resource is not preferred (e.g., conflict detected onreserved resource), no transmission on the first resource, and indicateNACK on the second resource. This option requires 1 PSFCH transmissionin all cases.

A third sub-option is noted as Option 2-3 (e.g., Groupcast HARQ-ACKreporting option (1)). In case of ACK and reserved resource is preferred(e.g., no conflict detected on reserved resource), no transmission onthe first resource, and indicate reserved resource is preferred on thesecond resource. In case of ACK and reserved resource is not preferred(e.g., conflict detected on reserved resource), no transmission on thefirst resource, and indicate reserved resource is not preferred on thesecond resource. In case of NACK and reserved resource is preferred(e.g., no conflict detected on reserved resource), indicate NACK on thefirst resource, and indicate reserved resource is preferred on thesecond resource. In case of NACK and reserved resource is not preferred(e.g., conflict detected on reserved resource), indicate NACK on thefirst resource, and indicate reserved resource is not preferred on thesecond resource. This option requires 2 PSFCH (and/or feedback channel)transmissions in case of NACK. There is no ACK feedback with GroupcastHARQ-ACK reporting option (1). This scheme can be extended to indicatethe conflict status for each of N pre-indicated/reserved SL resources byhaving a PSFCH (feedback channel) for each pre-indicated/reserved SLresource in addition to the PSFCH for HARQ-ACK status. Therefore, therecan be a total of N+1 PSFCH (and/or feedback channel) resources.Alternatively, the conflict status for the of N pre-indicated/reservedSL resources can be indicated using a single PSFCH (feedback channel)resource conveying one bit as described earlier, in this case only 2PSFCH (and/or feedback channel) resources are needed. Alternatively, theN PSFCHes (feedback channels) can be replaced by one PSFCH (feedbackchannel) carrying N bits.

A fourth sub-option is noted as Option 2-4 (Single PSFCH Resource)(e.g., for Groupcast HARQ-ACK reporting option (1)). In case of ACK andreserved resource is preferred (e.g., no conflict detected on reservedresource), no transmission on PSFCH resource. In case of ACK andreserved resource is not preferred (e.g., conflict detected on reservedresource), transmit a first cyclic shift corresponding topre-indicated/reserved resource not preferred. In case of NACK andreserved resource is preferred (e.g., no conflict detected on reservedresource), transmit a second cyclic shift corresponding to NACK. In caseof NACK and reserved resource is not preferred (e.g., conflict detectedon reserved resource), transmit a first and a second cyclic shiftcorresponding to pre-indicated/reserved resource not preferred and NACK.This option requires transmission of up to two cyclic shifts on a PSFCHresource. Alternatively, in case of NACK and reserved resource is notpreferred (e.g., conflict detected on reserved resource), transmit athird cyclic shift corresponding to pre-indicated/reserved resource notpreferred and NACK. There is no ACK feedback with Groupcast HARQ-ACKreporting option (1).

In case of Groupcast HARQ-ACK Feedback, the PSFCH resource indicatingpreferred (e.g., no conflict detected on reserved resource) ornon-preferred pre-indicated/reserved resource (e.g., a resource that hasa collision or conflict) can be in a first example UE specific, or itcan be in a second example UE-common (i.e., one resource for all UEs inthe groupcast set). When the UE is transmitting feedback to indicatepreferred (e.g., no conflict detected on reserved resource) ornon-preferred (e.g., conflict detected on reserved resource)pre-indicated/reserved resource, it can in a first example transmit alogical level for a preferred pre-indicated/reserved resource andtransmit a second logical level for non-preferred pre-indicated/reservedresource; or in a second example it can transmit a signal for apreferred pre-indicated/reserved resource and no transmission (DTX) fornon-preferred pre-indicated/reserved resource; or in a third example itcan transmit a signal for a non-preferred pre-indicated/reservedresource and no transmission (DTX) for a preferredpre-indicated/reserved resource

For example (example 3.1.1.3), a UE-A does not transmit HARQ-ACKfeedback on PSFCH in response to a PSCCH/PSSCH transmission in a SL slot(e.g., blind retransmissions or in response with a PSCCH with reservedresources and without an associated PSSCH). If the PSSCH transmission isnot successfully decoded or is not scheduled by the PSCCH, a UE-B can(re-)transmit on a pre-indicated/reserved resource if UE-A determinesthat it is available (i.e., no conflict detected on reserved resource).

If UE-A determines that the pre-indicated or reserved SL resource doesnot overlap or collide in time and frequency domains with a second SLtransmission, or if the pre-indicated or reserved SL resource collidesor overlaps in time and frequency domains with a second SL transmission,but has the highest priority and/or the highest SL RSRP and/or SL RSRPabove a threshold, wherein a second SL transmission can be determinedfrom a pre-indication/reserved signal(s) received by UE-A and/or UE-A'ssensing information and/or UE-A's own SL transmission (with overlap intime with the pre-indicated/reserved resource of UE-B). A conflict dueto sensing can take into account the SL RSRP of the SL resourcesinvolved in the collision for determining whether apre-indicated/reserved SL resource from UE-B has a conflict, asdescribed earlier in this disclosure. UE-A can indicate to UE-B that thepre-indicated/reserved resource is preferred for SL transmission, e.g.,that the pre-indicated/reserved resource has no conflict.

Alternatively, if the UE-A determines that the pre-indicated or reservedSL resource collides or overlaps in time and frequency domains withanother SL transmission, but has a lower priority and/or lower SL RSRPthan any of the colliding SL transmissions and/or SL RSRP below athreshold, wherein a colliding SL transmission can be determined from apre-indication/reserved signal(s) received by UE-A and/or UE-A's sensinginformation and/or UE-A's own SL transmission (with overlap in time withthe pre-indicated/reserved resource of UE-B). UE-A can indicate to UE-Bthat the pre-indicated/reserved resource is not preferred (e.g., has adetected conflict) for SL transmission. UE-B can reselect a differentresource for SL transmission based on its own sensing and/or inter-UEco-ordination information from other UEs.

If the pre-indication/reservation signal from UE-B to UE-A includes morethan one (e.g., N, with N>1) resource, UE-A can determine a singleoutcome for that status of the N pre-indicated/reserved resource.According to one of the following. (1) If any resourcepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (allpre-indicated/configured SL resources have no conflict) UE-A indicatesto UE-B resources have no conflict (e.g., preferred). (2) If allpre-indicated/configured SL resources have a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (at least onepre-indicated/configured SL resource has no conflict) UE-A indicates toUE-B resources have no conflict (e.g., preferred). (3) If first in-timepre-indicated/configured SL resource has a conflict, UE-A indicates toUE-B resources have a conflict (e.g., not preferred), else (firstin-time pre-indicated/configured SL resource has no conflict) UE-Aindicates to UE-B resources have no conflict (e.g., preferred)

In this example, the PSFCH-like (or feedback) channel or signal canindicate one of two levels. The regular PSFCH design of NR release 16can be reused for the feedback channel.

This scheme can be extended to indicate the conflict status for each ofN pre-indicated/reserved SL resources by having a PSFCH (feedbackchannel) for each pre-indicated/reserved SL resource in addition to thePSFCH for HARQ-ACK status. Therefore, there can be a total of N PSFCHresources. Alternatively, the conflict status for the of Npre-indicated/reserved SL resources can be indicated using a singlePSFCH resource conveying one bit as described earlier. Alternatively,the N PSFCHes (feedback channels) can be replaced by one PSFCH (feedbackchannel) carrying N bits.

For another example (example 3.1.2), the PSCCH transmission is notassociated with a PSSCH transmission in a same SL slot. The PSCCHincludes SCI that indicates N SL resources reserved in a future SL slot.A UE can (re-)transmit on a pre-indicated/reserved resource if UE-Adetermines that it is available. In one example N=1. In another example,N=2. In another example, N is larger than 2 and specified in the systemspecification and/or pre-configured and/or configured or updated by RRCsignaling and/or MAC CE signaling and/or L1 control signaling.

If UE-A determines that the pre-indicated or reserved SL resource doesnot overlap or collide in time and frequency domains with a second SLtransmission, or if the pre-indicated or reserved SL resource collidesor overlaps in time and frequency domains with a second SL transmission,but has the highest priority and/or the highest SL RSRP and/or SL RSRPabove a threshold, wherein a second SL transmission can be determinedfrom a pre-indication/reserved signal(s) received by UE-A and/or UE-A'ssensing information and/or UE-A's own SL transmission (with overlap intime with the pre-indicated/reserved resource of UE-B). A conflict dueto sensing can take into account the SL RSRP of the SL resourcesinvolved in the collision for determining whether apre-indicated/reserved SL resource from UE-B has a conflict, asdescribed earlier in this disclosure. UE-A can indicate to UE-B that thepre-indicated/reserved resource is preferred for SL transmission, e.g.,that the pre-indicated/reserved resource has no conflict.

Alternatively, if UE-A determines that the pre-indicated or reserved SLresource collides or overlaps in time and frequency domains with anotherSL transmission, but has a lower priority and/or lower SL RSRP than anyof the colliding SL transmissions and/or SL RSRP below a threshold,wherein a colliding SL transmission can be determined from apre-indication/reserved signal(s) received by UE-A and/or UE-A's sensinginformation and/or UE-A's own SL transmission (with overlap in time withthe pre-indicated/reserved resource of UE-B). UE-A can indicate to UE-Bthat the pre-indicated/reserved resource is not preferred (e.g., has adetected conflict) for SL transmission. UE-B can reselect a differentresource for SL transmission based on its own sensing and/or inter-UEco-ordination information from other UEs.

In this example the PSFCH-like (or feedback) channel or signal canindicate one of two levels. The regular PSFCH design of NR release 16can be reused.

FIG. 14 illustrates an example signaling 1400 using a PSCCH and/or PSSCHfor a resource reservation for a SL transmission on a future SL resourceaccording to embodiments of present disclosure. FIG. 14 is an examplefollowing example 3.1.1, described above. Two UE-Bs (i.e., UE-B1 andUE-B2) transmit PSCCH/PSSCH that includes a resource reservation for aSL transmission on a future SL resource. The reserved resource of UE-B1and UE-B2 overlap. UE-A fails to decode the transmissions of UE-B1 andUE-B2. UE-A determines that the resources reserved by UE-B1 and UE-B2overlap or collide. UE-A determines which SL transmission (UE-B1 orUE-B2) has a higher priority and/or higher SL RSRP and/or SL RSRP abovea threshold. For example, this can be determined based on the priorityfield of the first stage SCI in PSCCH or based on UE-A's ownimplementation. For example, in this case, the UE-B2 can have a SLtransmission with a higher priority than the priority of a SLtransmission from UE-B1. UE-A indicates a NACK to UE-B1 (if applicable)and that the pre-indicated or reserved SL resource is not preferred.UE-A indicates a NACK to UE-B2 (if applicable) and that thepre-indicated or reserved SL resource is preferred. UE-B2 can be proceedwith the SL (re-)transmission on the pre-indicated or reserved resource.UE-B1 can perform resource reselection to a select a different SLresource for the SL (re-)transmission.

For another example (example 3.2), the pre-indication/reservation signalcan be included in PSCCH and/or PSSCH transmission following theexamples of component 2, and the grant/trigger signaling can be includedin a PSFCH-like transmission or feedback channel following the examplesof component 1.

For yet another example (example 3.3), the pre-indication/reservationsignal can be included in PSFCH-like transmission following the examplesof component 1, and the grant/trigger signaling can be included in aPSCCH transmission and/or PSSCH transmission following the examples ofcomponent 2.

Embodiments of the present disclosure also describe converting physicalduration to logical sidelink slots. The following examples andembodiments describe converting physical duration to logical sidelinkslots.

Additionally, the set of slots belonging to the SL resource pool, ofEquation (1), are based on the following. Each resource pool has acorresponding bitmap (b₀, b₁, . . . , b_(L) _(bitmap) ₋₁) of lengthL_(bitmap). A slot t_(k) belongs to the bitmap if b_(k mod L) _(bitmap)=1. The remaining slots are indexed successively staring from 0, 1, . .. T′_(MAX)−1. Where, T′_(MAX) is the number of remaining slots in theset.

In certain embodiments, slots can be numbered (indexed) as physicalslots or logical slots, wherein physical slots, include all slotsnumbered sequential, while logical slots include only slots that can beallocated to sidelink resource pool as described above numberedsequentially. The conversion from a physical duration, P_(rsvp,) inmilli-second to a logical slots, P′_(rsvp), has previously beendescribed in Equation (9).

$\begin{matrix}{P_{rsvp}^{\prime} = \left\lceil {\frac{N}{20\mspace{14mu}{ms}} \times P_{rsvp}} \right\rceil} & (9)\end{matrix}$Here, N is the number of slots that can be used for SL transmissionwithin 20 ms of the configured UL-DL.

It is noted that 3GPP Release 16 is the first NR release to includesidelink through work item “5G V2X with NR sidelink”, the mechanismsintroduced focused mainly on vehicle-to-everything (V2X), and can beused for public safety when the service requirement can be met. Inrelease 16, the formula for conversion from physical slots (physicalduration) to logical slots is based on a given resource reservationperiod P_(rsvp) in milliseconds that is converted to a period P′_(rsvp)in logical slots as Equation (9).

The principle of this conversion is to ensure that the duration inlogical slots, i.e., P′_(rsvp) is roughly equal to the physical durationP_(rsvp). This equation does not take into account (i) the resourcebitmap, wherein not all SL slots can be used for a SL resource pool and(ii) the S-SSB slots, N_(S-SSB), and the reserved slots, not included inthe resource pool, N_(reserved).

Embodiments of the present disclosure take into consideration that theduration in logical slots can be longer than the physical duration.Accordingly, embodiments of the present disclosure modify Equation (9)to better align the logical slot duration with the physical duration.

Furthermore, for configured grant Type 1, for determining the S^(th)sidelink grant is described in Equation (10), below. Additionally, forconfigured grant Type 2, for determining the Sth sidelink grant isdescribed in Equation (11).

$\begin{matrix}\begin{matrix}\begin{matrix}\begin{matrix}{{\left( {{SFN} \times {numberOfSLSlotsPerFrame}} \right) + {{logical}\mspace{14mu}{slot}\mspace{14mu}{number}}}\mspace{14mu}} \\{\left. {{in}\mspace{14mu}{the}\mspace{14mu}{frame}} \right\rbrack = \left( {{sl} - {TimeReferenceSFN} - {{Type}\; 1 \times}} \right.}\end{matrix} \\{{numberOfSLSlotsPerFrame} + {sl} - {{TimeOffsetCGType}\; 1} + {S \times}}\end{matrix} \\{\left. {PeriodicitySL} \right)\mspace{14mu}{modulo}\mspace{14mu}\left( {1024 \times {numberOfSLSlotsPerFrame}} \right)}\end{matrix} & (10) \\\begin{matrix}\begin{matrix}\begin{matrix}{{\left( {{SFN} \times {numberOfSLSlotsPerFrame}} \right) + {{logical}\mspace{14mu}{slot}\mspace{14mu}{number}}}\;} \\{\left. {{in}\mspace{14mu}{the}\mspace{14mu}{frame}} \right\rbrack = \left\lbrack \left( {{{SFNstart}\mspace{14mu}{time} \times {numberOfSLSlotsPerFrame}} +} \right. \right.}\end{matrix} \\\left. {\left. {{slotstart}\mspace{14mu}{time}} \right) + {S \times {PeriodicitySL}}} \right\rbrack\end{matrix} \\{{modulo}\mspace{14mu}{\left( {1024 \times {numberOfSLSlotsPerFrame}} \right).}}\end{matrix} & (11)\end{matrix}$Here,

${PeriodicitySL}{= {\left\lceil {\frac{N}{20\mspace{14mu}{ms}} \times {sl\_ periodCG}} \right\rceil.}}$Also, numberOfSLSlotsPerFrame refers to the number of logical slots thatcan be used for SL transmission in the frame. N refers to the number ofslots that can be used for SL transmission within 20 ms, ofTDD-UL-DL-ConfigCommon of the serving cell, if provided, orsl-TDD-Configuration, if provided, or sl-TDD-Config of the receivedPSBCH. SFN_(start time) and slot_(start time) are the SFN and logicalslot, respectively, of the first transmission opportunity of PSCCH/PSSCHwhere the configured sidelink grant was (re-) initialised.

The above equations for configured grant Type 1 and configured grantType 2 do not take into account that (i) the resource bitmap, whereinnot all SL slots can be used for a SL resource pool and (ii) the S-SSBslots, N_(S-SSB), and the reserved slots, not included in the resourcepool, N_(reserved).

Accordingly, embodiments of the present disclosure describe signalingand methods for converting a physical duration to a logical slotduration. Embodiments of the present disclosure also describe equationsfor the resources of configured grant Type 1 and configured grant type2.

In certain embodiments, N is the number of slots that can be used for SLtransmission within 20 ms, which excludes Non-SL slots. In 1024 frames(10240 ms). The number of slots that can be used for SL transmissionexcluding Non-SL slots, is described in Equation (12).

$\begin{matrix}{{{2^{\mu} \times 10240} - N_{nonSL}} = {512 \cdot N}} & (12)\end{matrix}$

In addition to N nonSL slots, S-SBB slots (N_(S-SSB)) and reservedslots, not included in the resource pool, (N_(reserved)) are excludedfrom the SL slots that may be included in a SL resource pool. The numberof slots that may be included in a SL resource pool across 1024 framesis expressed in Equation (13). Additionally, the number of SL slots thatmay be included in a SL resource pool in 20 ms is expressed in Equation(14).

$\begin{matrix}{{{2^{\mu} \times 10240} - N_{nonSL} - N_{S - {SSB}} - N_{reserved}} = {{512 \cdot N} - N_{S - {SSB}} - N_{reserved}}} & (13) \\{N - \frac{N_{S - {SSB}} + N_{reserved}}{512}} & (14)\end{matrix}$

Furthermore, the slots that actually belong to a resource pool is givenby a bitmap of length L_(bitmap). The number of such slots (i.e., slotswhere the corresponding bit is logical 1) can be expressed asL_(bitmap,one). Accordingly, the total number of slots in a SL resourcepool across 1024 frames described in Equation (15). Therefore, thenumber of slots in a SL resource pool within 20 ms is described inEquation (16).

$\begin{matrix}{{\left( {{2^{\mu} \times 10240} - N_{nonSL} - N_{S - {SSB}} - N_{reserved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}} = {\left( {{512 \cdot N} - N_{S - {SSB}} - N_{reserved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (15) \\{N_{{SL} - {RP}} = {\left( {N - \frac{N_{S - {SSB}} + N_{reserved}}{512}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (16)\end{matrix}$

The conversion from a physical duration, P_(rsvp), in milli-second to alogical slots, P′_(rsvp), is described in Equation (17). In Equation(17), the expression, N_(SL-BP), is defined in Equation (17.1).

$\begin{matrix}{P_{rsvp}^{\prime} = \left\lceil {\frac{N_{{SL} - {RP}}}{20\mspace{14mu}{ms}} \times P_{rsvp}} \right\rceil} & (17) \\{N_{{SL} - {RP}} = {\left( {N - \frac{N_{S - {SSB}} + N_{reserved}}{512}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (17.1)\end{matrix}$Here, the expression N is the number of slots that can be used for SL in20 ms interval. The expression, N_(S-SSB) is the number of S-SSB slotsacross 1024 frames. The expression, N_(reserved) is the number ofreserved slots, not included in the resource pool, across 1024 frames.The expression, L_(bitmap) is the length of the bitmap of the SLresource pool. The expression, L_(bitmap,one) is the number of bits inthe bitmap of the SL resource pool with logical 1. N_(SL-BP) is thenumber of SL slots within a resource pool within 20 ms interval.N_(SL-BP) can be a number that includes a fraction part.

In certain embodiments, the expression N_(reserved) is ignored, such aswhen the value is small relative to the number of available slots. Whenthe expression N_(reserved) is ignored, Equation 17.1 is described inEquation (18).

$\begin{matrix}{N_{{SL} - {RP}} = {\left( {N - \frac{N_{S - {SSB}}}{512}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (18)\end{matrix}$

In certain embodiments, the expression N_(S-SSB,20) is the number ofS-SSB slots in 20 ms, wherein the number can be an integer or afraction. When the number of S-SSBs varies from one 20 ms interval tothe next, N_(S-SSB,20) is the average number of S-SSB slots across 20ms, averaged across 1024 frames, and described in Equation (19).

$\begin{matrix}{N_{{SL} - {RP}} = {\left( {N - N_{{S - {SSB}},{20}}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (19)\end{matrix}$

In certain embodiments, the expression N excludes the S-SSB slots. Ifthe number of S-SSB slots is the same across each 20 ms interval, N isan integer, if the number of S-SSB slots varies across 20 ms intervals,N is the average number of the slots that can be included in a SLresource pool across 20 ms averaged across 1024 frames, as described inEquation (20).

$\begin{matrix}{N_{{SL} - {RP}} = {N \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}} & (20)\end{matrix}$

In certain embodiments, the expression N is the average number of SLslots in a SL resource pool, as the number of SL slots in a resourcepool can vary from one 20 ms interval to the next, N is determined asthe average number of SL slots in a sidelink resource pool averagedacross 1024 frames, as described in Equation (21).

$\begin{matrix}{N_{{SL} - {RP}} = N} & (21)\end{matrix}$

Accordingly, N×512 is the total number of slots that can be used for SLtransmission in 1024 frames or 10240 ms. Then N_(SL-RP) is the number ofslots that can be used for SL transmission in 20 ms, as described inEquation (22), Equation (23), and Equation (24) based on Equation (17)and Equation (17.1).

$\begin{matrix}{P_{rsvp}^{\prime} = \left\lceil {\frac{N_{{SL} - {RP}}}{20{ms}} \times P_{rsvp}} \right\rceil} & (22)\end{matrix}$ $\begin{matrix}{= \left\lceil {\frac{1}{20{ms}}\left( {N - \frac{N_{S - {SSB}} + N_{reserved}}{512}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}} \times P_{rsvp}} \right\rceil} & (23)\end{matrix}$ $\begin{matrix}\left\lceil {\frac{1}{512 \times 20{ms}}\left( {{512 \times N} - N_{S - {SSB}} - N_{{rese}rved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}} \times P_{rsvp}} \right\rceil & (24)\end{matrix}$

It is noted that the expression,

${\left( {{512 \times N} - N_{S - {SSB}} - N_{reserved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}},$is the number of SL slots in a resource pool in 1024 frames or 10240 ms,which can be denoted as T′_(max). Accordingly, Equation (25), below,modifies Equation (22), above.

$\begin{matrix}{P_{rsvp}^{\prime} = \left\lceil {\frac{T_{\max}^{\prime}}{10240{ms}} \times P_{rsvp}} \right\rceil} & (25)\end{matrix}$

Now we consider the equations to determine the slots for configuredgrant. After (i) removing the S-SSB slots, and (ii) removing thereserved slots, not included in the resource pool, and (iii) applyingthe bitmap, the number of slots in a frame (10 ms) that are in aresource pool varies from one frame to the next. Therefore, to get thetotal number slots in a resource pool from the start of system framenumber 0 to the start of system frame number SFN, the slots of aresource pool in a frame are summed, as described in Equation (26).

$\begin{matrix}{\sum_{i = 0}^{{SFN} - 1}{{SlotsOfSLR}esourcePoolinFram{e(i)}}} & (26)\end{matrix}$Here, the expression SlotsOfSLResourcePoolinFrame(i) is the number ofslots of a resource pool in a frame with index i. Similarly, forsl_TimeReferenceSFF_Type1, the total number of slots of a resource poolfrom the start of system frame number 0 to the start of system framenumber sl_TimeReferenceSFF_Type1 is described in Equation (27).

$\begin{matrix}{\sum_{i = 0}^{{{sl}\_{TimeReferenceSF}FType1} - 1}{Slo{tsOfSLR}esourcePoolinFram{e(i)}}} & (27)\end{matrix}$

The conversion of the configured grant period in milli-seconds to slotsof a resource pool follows the same principle as has been previouslypresented for P_(rsvp), and represented in Equation (28).

$\begin{matrix}{{PeriodicitySL} = \left\lceil {\frac{T_{\max}^{\prime}}{10240{ms}} \times {sl\_ periodCG}} \right\rceil} & (28)\end{matrix}$

Therefore, for configured grant Type 1, the equation for determining theSL slots within a resource pool for S^(th) sidelink grant is describedin Equation (29). Equation (30) described the scenario of whensl_TimeReferenceSFF_Type1ϵ{0,512} and as the reserved slots are evenlydistributed throughout the 1024 frames. Equation (31) is the result ofcombining Equation (29) and Equation (30).

$\begin{matrix}{\left\lbrack {\left( {\sum_{i = 0}^{{SFN} - 1}{Slo{tsOfSLR}esourcePoolinFram{e(i)}}} \right) + {{logical}{slot}{number}{in}{the}{frame}}} \right\rbrack = {\left( {{\sum_{i = 0}^{{sl} - {T{imeReferenceSF}FType1} - 1}{Slo{tsOfSLR}esourcePoolinFram{e(i)}}} + {sl} - {{TimeOffsetCGType}1} + {S \times {PeriodicitySL}}} \right){modulo}\left( T_{\max}^{\prime} \right)}} & (29)\end{matrix}$ $\begin{matrix}{{\sum_{i = 0}^{{sl} - {T{imeReferenceSF}FType1} - 1}{{SlotsOfSLR}esourcePoolinFram{e(i)}}} = {\left\lceil {T_{\max}^{\prime}\frac{{sl} - {TimeReferenceSFF\_ Type1}}{1024}} \right\rceil.}} & (30)\end{matrix}$ $\begin{matrix}{\left\lbrack {\left( {\sum_{i = 0}^{{SFN} - 1}{Slo{tsOfSLR}esourcePoolinFram{e(i)}}} \right) + {{logical}{slot}{number}{in}{the}{frame}}} \right\rbrack = {\left( {\left\lceil {T_{\max}^{\prime}\frac{{sl} - {TimeReferenceSFF\_ Type1}}{1024}} \right\rceil + {sl} - {{TimeOffsetCGType}1} + {S \times {PeriodicitySL}}} \right){modulo}{\left( T_{\max}^{\prime} \right).}}} & (31)\end{matrix}$

If the S−1 configured grant Type 1 SL transmission is in logical slotSL_(S-1), the S configured grant SL transmission is in logical slotSL_(S), wherein, according to equation (31) SL_(S)=mod(SL_(S-1)+PeriodicitySL, T′_(max)).

Similarly, for configured grant Type 2, Equation (32) describesdetermining the SL slots within a resource pool for S^(th) sidelink. Itis noted that the expressions, SFN_(start time) and slot_(start time)are the SFN and logical slot, respectively, of the first transmissionopportunity of PSSCH where the configured sidelink grant was(re-)initialised.

$\begin{matrix}{{\left\lbrack {\left( {\sum_{i = 0}^{{SFN} - 1}{Slo{tsOfSLR}esourcePoolinFram{e(i)}}} \right) + {{logical}{slot}{number}{in}{the}{frame}}} \right\rbrack } = {{\left\lbrack \text{⁠}{\left( {{\sum_{i = 0}^{{{SFNstart}{time}} - 1}{{SlotsOfSLReso}urcePoolinFram{e(i)}}} + {slot}_{{start}{time}}} \right) + {S \times {PeriodicitySL}}} \right\rbrack{modulo}{\left( T_{\max}^{\prime} \right).}}}} & (32)\end{matrix}$

If the S−1 configured grant Type 2 SL transmission is in logical slotSL_(S-1), the S configured grant SL transmission is in logical slotSL_(S), wherein, according to equation (32) SL_(S)=mod(SL_(S-1)+PeriodicitySL, T′_(max)).

The above flowcharts and signaling diagrams illustrate example methodsthat can be implemented in accordance with the principles of the presentdisclosure and various changes could be made to the methods illustratedin the flowcharts herein. For example, while shown as a series of steps,various steps in each figure could overlap, occur in parallel, occur ina different order, or occur multiple times. In another example, stepsmay be omitted or replaced by other steps.

Although the figures illustrate different examples of user equipment,various changes may be made to the figures. For example, the userequipment can include any number of each component in any suitablearrangement. In general, the figures do not limit the scope of thisdisclosure to any particular configuration(s). Moreover, while figuresillustrate operational environments in which various user equipmentfeatures disclosed in this patent document can be used, these featurescan be used in any other suitable system.

Although the present disclosure has been described with exemplaryembodiments, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims. None of the description in this application should be read asimplying that any particular element, step, or function is an essentialelement that must be included in the claims scope. The scope of patentedsubject matter is defined by the claims.

What is claimed is:
 1. A first user equipment (UE) in a communicationsystem, the first UE comprising: a processor configured to: decode aphysical sidelink control channel (PSCCH), wherein the PSCCH includes aresource reservation period (P_(rsvp)) field in units of milliseconds(ms); and convert P_(rsvp) into P′_(rsvp) in logical slots, wherein:P_(rsvp) is multiplied by a ratio L/T and rounded-up based on a ceilingfunction to obtain P′_(rsvp), T is a period in units of ms, L is a valuerelated to logical slots in a resource pool in the period T, and L isdetermined as a number of slots corresponding to bits having value 1within a bitmap, among a set of slots in the period T excluding at leastone non-SL slot, at least one sidelink synchronization signal block(S-SSB) slot, and at least one reserved slot.
 2. The first UE of claim1, wherein: the processor is further configured to identify whether aconflict occurs on a first reserved resource for a second UE, and theconflict occurs on the first reserved resource in response to the firstreserved resource being overlapped, in time, with a resource fortransmission of the first UE.
 3. The first UE of claim 1, wherein: theprocessor is further configured to identify whether a conflict occurs ona first reserved resource for a second UE, and the conflict occurs onthe first reserved resource in response to the first reserved resourcebeing overlapped, in time and frequency, with a second reserved resourcefor a PSSCH of a third UE.
 4. The first UE of claim 3, wherein areference signal received power (RSRP) of the third UE is above a RSRPthreshold, and wherein the RSRP threshold depends on a first priorityvalue associated with the first reserved resource and a second priorityvalue associated with the second reserved resource.
 5. The first UE ofclaim 1, wherein T=10240 ms.
 6. The first UE of claim 5, wherein:${L = {\left( {{2^{\mu} \times 10240} - N_{nonSL} - N_{S - {SSB}} - N_{reserved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}},$μ; is a sub-carrier spacing configuration, N_(nonSL): is a number ofnon-SL slots in 1024 frames, N_(S-SSB): is a number of S-SSB slots in1024 frames, N_(reserved): is a number of reserved slots in 1024 frames,L_(bitmap,one): is a number of bits having value 1 in the bitmapassociated with the resource pool, and L_(bitmap): is a total number ofbits in the bitmap associated with the resource pool.
 7. The first UE ofclaim 1, wherein: a configured grant period (sl_periodCG) inmilliseconds is converted to a period (PeriodicitySL) in logical slotsas:${PeriodicitySL} = \left\lceil {\frac{{T^{\prime}}_{\max}}{10240\mspace{14mu}{ms}} \times {sl\_ periodCG}} \right\rceil$8. The first UE of claim 7, wherein a logical slot for S^(th) sidelinkgrant for a sidelink configured grant type 1 is determined as:(sl-ReferenceSlotCG-Type1+sl-TimeOffsetCGType1+S×PeriodicitySL)modulo(T′_(max)),wherein: sl-ReferenceSlotCG-Type 1: is a reference logical slotdetermined as sl-ReferenceSlotCG-Type 1=Σ_(i=0)^(sl-TimeReferenceSFN_Type1-1)SlotsOfSLResourcePoolinFrame(i),SlotsOfSLResourcePoolinFrame(i): is a number of slots of a resource poolin a frame with index i, sl_TimeReferenceSFN_Type1: is a system framenumber configured as 0 or 512, and sl-TimeOffsetCGType1: is a slotoffset with respect to the reference logical slot.
 9. The first UE ofclaim 7, wherein a logical slot for S^(th) sidelink grant for a sidelinkconfigured grant type 2 is determined as:[sl-StartSlotCG-Type2+S×PeriodicitySL] modulo (T′_(max)), whereinsl-StartSlotCG-Type2 is a logical slot of a first transmissionopportunity of PSSCH where the configured sidelink grant was(re-)initialized, and determined as sl-StartSlotCG-Type2=(Σ_(i=0)^(SFNstart time-1) SlotsofSLResourcePoolinFrame(i)+slot_(start time)),SFN_(start time) and slot_(start time) being a subframe number (SFN) andlogical slot, respectively, of the first transmission opportunity ofPSSCH where the configured sidelink grant was (re-)initialized.
 10. Amethod performed by a first user equipment (UE) in a communicationsystem, the method comprising: decoding a physical sidelink controlchannel (PSCCH), wherein the PSCCH includes a resource reservationperiod (P_(rsvp)) field in units of milliseconds (ms); and convertingP_(rsvp) into P′_(rsvp) in logical slots, wherein: P_(rsvp) ismultiplied by a ratio L/T and rounded-up based on a ceiling function toobtain P′_(rsvp), T is a period in units of ms, L is a value related tological slots in a resource pool in the period T, and L is determined asa number of slots corresponding to bits having value 1 within a bitmap,among a set of slots in the period T excluding at least one non-SL slot,at least one sidelink synchronization signal block (S-SSB) slot, and atleast one reserved slot.
 11. The method of claim 10, further comprising:identifying whether a conflict occurs on a first reserved resource for asecond UE, wherein the conflict occurs on the first reserved resource inresponse to the first reserved resource being overlapped, in time, witha resource for transmission of the first UE.
 12. The method of claim 10,further comprising: identifying whether a conflict occurs on a firstreserved resource for a second UE, wherein the conflict occurs on thefirst reserved resource in response to the first reserved resource beingoverlapped, in time and frequency, with a second reserved resource for aPSSCH of a third UE.
 13. The method of claim 12, wherein a referencesignal received power (RSRP) of the third UE is above a RSRP threshold,and wherein the RSRP threshold depends on a first priority valueassociated with the first reserved resource and a second priority valueassociated with the second reserved resource.
 14. The method of claim10, wherein T=10240 ms.
 15. The method of claim 14, wherein:$L = {\left( {{2^{\mu} \times 10240} - N_{nonSL} - N_{S - {SSB}} - N_{reserved}} \right) \times \frac{L_{{bitmap},{one}}}{L_{bitmap}}}$μ: is a sub-carrier spacing configuration, N_(nonSL): is a number ofnon-SL slots in 1024 frames, N_(S-SSB): is a number of S-SSB slots in1024 frames, N_(reserved): is a number of reserved slots in 1024 frames,L_(bitmap,one): is a number of bits having value 1 in the bitmapassociated with the resource pool, and L_(bitmap): is a total number ofbits in the bitmap associated with the resource pool.
 16. The method ofclaim 10, wherein: a configured grant period (sl_periodCG) inmilliseconds is converted to a period (PeriodicitySL) in logical slotsas:${PeriodicitySL} = \left\lceil {\frac{T_{\max}^{\prime}}{10240{ms}} \times {sl\_ periodCG}} \right\rceil$17. The method of claim 16, wherein a logical slot for S^(th) sidelinkgrant for a sidelink configured grant type 1 is determined as:(sl-ReferenceSlotCG-Type 1+sl-TimeOffsetCGType1+S×PeriodicitySL) modulo(T′_(max)), wherein: sl-ReferenceSlotCG-Type1: is a reference logicalslot determined as sl-ReferenceSlotCG-Type 1=Σ_(i=0)^(sl-TimeReferenceSFN_Typ1-1) SlotsOfSLResourcePoolinFrame(i),SlotsOfSLResourcePoolinFrame(i): is a number of slots of a resource poolin a frame with index i, sl_TimeReferenceSFN_Type1: is a system framenumber configured as 0 or 512, and sl-TimeOffsetCGType1: is a slotoffset with respect to the reference logical slot.
 18. The method ofclaim 16, wherein a logical slot for S^(th) sidelink grant for asidelink configured grant type 2 is determined as:[sl-StartSlotCG-Type2+S×PeriodicitySL] modulo (T′_(max)), whereinsl-StartSlotCG-Type2 is a logical slot of a first transmissionopportunity of PSSCH where the configured sidelink grant was(re-)initialized, and determined as sl-StartSlotCG-Type2=(Σ_(i=0)^(SFNstart time-1) SlotsOfSLResourcePoolinFrame(i)+slot_(start time)),SFN_(start time) and slot_(start time) being a subframe number (SFN) andlogical slot, respectively, of the first transmission opportunity ofPSSCH where the configured sidelink grant was (re-)initialized.